شككa single root meaning tadākhul — the interpenetration or interlocking of two things, one … (root shkk)

Al-shakk (الشك): the opposite of certainty (yaqīn). Al-shikka (الشكة): what is worn of weapons/armor — [repeated:] al-shikka: what is worn of weapons/armor, and one who wears it is shākk fī al-silāḥ (شاك في السلاح), from shakka yashukku shakkan; it may be lightened, so one says shākk fī al-silāḥ. It is also said: rather it is shākik (شاكك) [with a doubled kāf], the final kāf having been dropped and the first kāf left with its kasra unchanged. And it is said: rather it is shāʾik (شائك), from al-shawka (الشوكة, 'thorn'), assimilated to the dialect of those who say anā qāla (أنا قاله) for qāʾiluhu (قائله, 'its speaker'), and kabsh ṣāfin (كبش صاف), yawm rāḥin (يوم راح) for ṣāʾif (صائف, 'of summer') and rāʾiḥ (رائح, 'of the evening') — the hamza/yāʾ being dropped without altering the inflection, which remains in the nominative. And shakaktuhu bi-l-rumḥ (شككته بالرمح): I pierced him through with the spear.

Al-shakk: the opposite of certainty (yaqīn). You say shakaktu fī kadhā (شككت في كذا), tashakkaktu (تشككت), and shakkakanī fīhi fulān (شككني فيه فلان) [so-and-so made me doubt about it]. Also al-baʿīr yashukku shakkan: the camel limps with a slight limp. This is the sense in the verse of Dhū al-Rumma describing his she-camel, likening her to a wild ass: 'The wild ass leapt up from a mustered herd, as though it were one whose limping is manifest, or one with an aching side' — meaning: this she-camel leaps like the wild ass, which in its swaying gait from liveliness resembles one whose side aches (yashtakī janbahu). Al-shakk also means: clinging, sticking fast (al-luzūm wa-l-luṣūq). Abū Dahbal al-Jumaḥī said: 'My coat of mail (dirʿī dilāṣ), its rings interlocked (shakkuhā shakku ʿajab), and its weave compact (qātir), of thongs of yalab.' Al-shakūk (الشكوك): a she-camel whose hump is felt in doubt as to whether it is well-fattened, owing to the thickness of her wool, so her hump must be palpated. Al-shikka, with kasra: weapons/armor; also a broad piece of wood set into the eye of an axe-head or similar, to narrow it. One says rajulun shāku al-silāḥ and shākun fī al-silāḥ — the shāk fī al-silāḥ being one clad in complete armor. And qawmun shukkākun fī al-ḥadīd (a people fully armed in iron). Shakaktuhu bi-l-rumḥ: I pierced and threaded him through. ʿAntara said: 'And I pierced with the straight spear his garments — the noble man is not forbidden to the spear-points.' Al-shakīka: a faction of people. Al-shakāʾik: factions — from Abū ʿAmr.

Shīn (ش) and kāf (ك) form one root, parts of which are derived from one another, and it indicates interpenetration/interlocking (al-tadākhul). From this comes their saying shakaktuhu bi-l-rumḥ (شككته بالرمح), said when you thrust a spear into someone so that the spearhead penetrates into his body. The poet said: 'And I pierced (fa-shakaktu) with the straight spear his garments — the noble man is not forbidden to the spear-points.' This derives from the stringing-together (al-naẓm) of two things when they are 'shakka' [threaded]. From this chapter also comes al-shakk (الشك), the opposite of certainty (yaqīn); it is so called because the doubter (al-shākk) is as if the two possibilities (al-amrān) were threaded together for him upon a single pin (mishakk), so that he is not certain of either. Hence the derivation: you say shakaktu bayna waraqatayn (شككت بين ورقتين) when you insert a peg between two leaves/petals and join them together. From this chapter also is al-shikka (الشكة), what a person wears of weapons/armor; one says huwa shākk fī al-silāḥ (هو شاك في السلاح) [he is fully armed]. The weapon/armor is called shikka either because one is pierced/threaded with it, or because it is as if part of it is threaded (shukka) into another part. As for the verse of Dhū al-Rumma: 'The wild ass leapt up from a mustered herd (ʿānāt muʿaqqala), as though it were one whose limping (al-shakk) is manifest, or one with an aching side (janb)' — al-shakk here is said to be a slight limp; one says baʿīr shākk (a limping camel) and shakka yashukku shakkan. This is a sound analogy, since that is a pain which penetrates into the limb. It is also said that al-shakk is the sticking of the upper arm to the side; if this is correct, it is the more evident analogy. And al-shakāʾik (الشكائك) are factions/groups of people, singular shakīka (شكيكة); so named because when they separate, each faction still interlocks (yudākhilu) internally.

Al-shakk: the equal balance of two contradictories (al-naqīḍayn) in a person's mind and their equivalence to one another; this may occur because of two equally strong indications regarding the contradictories, or because of the absence of any indication for either. Al-shakk may concern whether a thing exists or not; or it may concern its genus — of what kind it is; or some of its attributes; or the purpose for which it was brought into existence. Al-shakk is a species of ignorance (jahl), but more specific than it, since jahl may be the total absence of knowledge regarding both contradictories; thus every shakk is jahl, but not every jahl is shakk. Allah, Exalted is He, says: 'And indeed they are in grave doubt (shakk) concerning it' [Hūd 11:110]; 'Nay, they are in doubt, amusing themselves' [al-Dukhān 44:9]; 'But if you are in doubt' [Yūnus 10:94]. Its derivation is either from shakaktu al-shayʾ, i.e., I pierced/tore it through, as he said: [entry continues]

Al-shakk: the opposite of certainty (yaqīn), plural shukūk (شكوك). You say shakaktu fī kadhā, tashakkaktu, shakka fī al-amr yashukku shakkan, and shakkakahu fīhi ghayruhu (someone else made him doubt it). Thaʿlab cites: 'Whoever claims he will conceal his love, until another makes him be doubted (yushakkik) concerning it — he is a liar,' meaning: until someone else casts doubt about him among others regarding it. And in the ḥadīth: 'I am more entitled to doubt (al-shakk) than Ibrāhīm,' [said] when the verse was revealed, '"Do you not believe?" He said, "Yes"' [Q. 2:260] — some, upon hearing the verse, said Ibrāhīm doubted while our Prophet did not; so he, peace be upon him, said out of humility and deference to Ibrāhīm: 'I am more entitled to doubt than Ibrāhīm,' meaning: I did not doubt, and I am beneath him [in rank], so how could he doubt? This is like his other ḥadīth: 'Do not prefer me over Yūnus ibn Mattā.' Muḥammad ibn al-Mukarram says: I have copied this passage as it stands, though I have reservation about the phrase 'and I am beneath him' — for in his statement 'I did not doubt, so how could he doubt' there was already sufficiency, making 'and I am beneath him' superfluous, nor does it correspond to 'Do not prefer me over Yūnus ibn Mattā,' which does not indicate that Yūnus is more excellent than him, but rather conveys courteous humility toward the prophets, peace upon them — i.e., even if I am more excellent than him, do not prefer me over him, out of humility and nobility of character on his part, peace be upon him. And their saying ṣumtu al-shahra alladhī shakkahu al-nās (I fasted the month which the people doubted) means: shukka fīhi al-nās (the people were in doubt about it). Al-shakūk: the she-camel whose hump is doubted [examined by touch] as to whether it carries fat, owing to the abundance of her wool, so her hump is felt; plural shukk (شك). Shakkahu bi-l-rumḥ wa-l-sahm wa-naḥwihimā yashukkuhu shakkan: he threaded/pierced him through; and it is said threading (al-intiẓām) is not termed shakk unless two things are joined by an arrow, spear, or the like. Shakaktuhu bi-l-rumḥ: I pierced him and threaded him through. Ṭarafa said: 'On both its sides, threaded (shakkā) into the palm-frond with a stitched [seam].' ʿAntara said: 'And I pierced with the straight spear his garments — the noble man is not forbidden to the spear-points.' And in the ḥadīth of al-Khudrī: a man entered his house and found a snake, so he pierced it (shakkahā) with the spear, i.e., ran it through and threaded it. Al-shikka: weapons/armor; it is also said al-shikka is what is worn of weapons; hence shākun fī silāḥihi (clad/entered into his armor); and anything you insert into another thing, you have 'shakaktahu' [threaded it]. Al-shikka: a broad piece of wood set into the eye of an axe-head or similar to narrow it. One says rajulun shāku al-silāḥ, shākun fī al-silāḥ — the shāk fī al-silāḥ being one clad in complete armor. And qawmun shukkākun fī al-ḥadīd. In the ḥadīth of the ransom of ʿAyyāsh ibn Abī Rabīʿa: the Prophet refused to ransom him except with the shikka (armor) of his father, i.e., his weapons. And in the ḥadīth of Miḥlam ibn Jaththāma: 'Then a man stood up, wearing a shikka [armor].' Shakka fī al-silāḥ: he donned it [entered into it]. One says huwa shākun fī al-silāḥ, and lightened, shāku al-silāḥ, shāku al-si... [entry continues]