توبIbn Fāris's own aṣl-entry for ت-و-ب is not among the excerpts given; by the other … (root twb)

One says: tubtu ilā Allāh (تبت إلى الله) tawbatan wa-matāban ('I turned back to God, in repentance and turning'), and 'I turn (atūbu) to God, that He may relent toward me (yatūbu ʿalayya)' — [as in the divine epithet] qābil al-tawb (قابل التوب), meaning qābil al-tawbah ('Accepter of repentance'), with the hāʾ dropped. And al-tawbah (التوبة) [also means] modesty/bashfulness (al-istiḥyāʾ); one says: 'your food is not the food of tawbah (طعام توبة)', meaning [food] that one need not be ashamed of or feel awkward about.

Al-tawbah (التوبة) is turning back from sin. In the ḥadīth: 'Regret is repentance (al-nadamu tawbah).' Likewise al-tawb (التوب) means the same. Al-Akhfash said: al-tawb is the plural of tawbah, like ʿawmah and ʿawm. One says tāba ilā Allāh (تاب إلى الله) tawbatan wa-matāban. And 'Allāh turned toward him' (tāba Allāhu ʿalayhi) means: He enabled him to attain it (repentance). In the book of Sībawayh, [it is noted that] al-tawbah is on the pattern of tafʿilah: al-tawbah. Istatābahu (استتابه) means: he asked him to repent. Al-tābūt (التابوت) — its origin is tābūwah, like tarqūwah ('collarbone'), being of the pattern faʿlūwah; when the wāw became quiescent, the feminine tāʾ marbūṭah turned into a plain tāʾ. Al-Qāsim ibn Maʿn said: the dialects of Quraysh and the Anṣār did not differ in anything in the Qurʾān except in [the word] al-tābūt: the dialect of Quraysh has it with tāʾ, and the dialect of the Anṣār has it with hāʾ.

Al-tawb (التوب) is the abandonment of sin in the most excellent manner, and it is the most eloquent mode of excuse-making. For excusing oneself takes three forms: the excuser either says 'I did not do it,' or 'I did it because of such-and-such,' or 'I did it and did wrong, and I have since desisted' — there is no fourth form, and this last is al-tawbah. Al-tawbah in the Sacred Law is: abandonment of sin because of its ugliness, regret over what one has committed, resolve never to return to it, and making up, through [renewed] deeds, for whatever [lost] deeds one is able to make up by repeating them. Whenever these four [elements] combine, the conditions of tawbah are complete. [As for] tāba ilā Allāh (تاب إلى الله) — the mention of 'to God' implies a turning-back [in devotion], as in: 'So turn in repentance to your Creator' (Qurʾān 2:54); 'and turn to God, all of you' (24:31); 'do they not turn to God?' (5:74). And tāba Allāhu ʿalayhi (تاب الله عليه) means: He accepted his repentance; from this: 'God has certainly turned in mercy to the Prophet and the Emigrants' (9:117); 'then He turned to them in mercy that they might repent' (9:118); 'so He turned to you in mercy and pardoned you' (2:187). Al-tāʾib (التائب) is used both for the one who offers repentance and for the one who accepts it: thus the servant is tāʾib toward God, and God is tāʾib toward His servant. Al-tawwāb (التواب) is the servant who repents much, by abandoning, at every moment, some of his sins in succession until he has abandoned them all; and this term is also applied to God Most High, because of His abundant acceptance of His servants' repentance, time after time. His saying: 'and whoever repents and does righteousness has truly turned to God in [accepted] repentance (matāban)' (25:71) means complete repentance, which is the combination of abandoning what is ugly and pursuing what is good. '[In] Him I have put my trust, and to Him is my return (matāb)' (13:30); 'indeed He is the Accepter of Repentance (al-tawwāb), the Merciful' (2:54).

Al-tawbah (التوبة) is turning back from sin. In the ḥadīth: 'Regret is repentance.' And al-tawb (التوب) is the same. Al-Akhfash said: al-tawb is the plural of tawbah, like ʿazmah and ʿazm. One says tāba ilā Allāh (تاب إلى الله), yatūbu, tawban wa-tawbatan wa-matāban: he turned back [in devotion] and returned from disobedience to obedience. As for the poet's saying: "I have turned (tubtu) to You, so accept my turning (tābatī), ...and I have fasted, my Lord, so accept my fasting (ṣāmatī)" he in fact meant tawbatī and ṣawmatī [with wāw], but substituted alif for wāw for a kind of ease [of pronunciation], since this poem is not entirely built on the muʾassas rhyme-pattern. Do you not see that it also contains: "I call upon You, O Lord, [to save me] from the Fire which You have prepared for the disbelievers on the Day of Resurrection" — here he used allatī, in which there is no alif taʾsīs [establishing letter]. And tāba Allāhu ʿalayhi (تاب الله عليه) means: He enabled him to attain it [repentance]. A man described as tawwāb (تواب) is one who turns [repeatedly] to God. And Allāh [described as] tawwāb means: He turns [in mercy] toward His servant. Regarding His saying, Most High: 'Forgiver of sin and Accepter of repentance (qābil al-tawb)' — it may be that He meant by it the verbal noun (maṣdar), like qawl, or that it is the plural of tawbah, like lawzah and lawz; this is the view of al-Mubarrid. Abū Manṣūr said: the basic sense of tāba is 'he returned to God, went back, and turned [in devotion].' Tāba Allāhu ʿalayhi means He returned to him with forgiveness. And His saying, Most High: 'and turn to God, all of you' means: return to His obedience and turn back to Him. Allāh al-Tawwāb (الله التواب) means: He turns [in mercy] toward His servant by His grace when [the servant] turns to Him [in repentance] from his sin. Istatabtu fulānan (استتبت فلانا) means: I offered him repentance for what he had committed, i.e., [invited him to] return and feel regret for what he had done. Istatābahu (استتابه) means: he asked him to repent. In the book of Sībawayh: al-titawbah (التتوبة) on the pattern of tafʿilah [belongs] to this [root]. Al-Jawharī mentioned in this entry al-tābūt (التابوت): [saying] its origin is tābūwah, like tarqūwah, of the pattern faʿlūwah; when the wāw became quiescent, the feminine tāʾ marbūṭah turned into a plain tāʾ. Al-Qāsim ibn Maʿn said: the dialects of Quraysh and the Anṣār did not differ in anything in the Qurʾān except in [the word] al-tābūt: the dialect of Quraysh has it with tāʾ, and the dialect of the Anṣār has it with hāʾ. Ibn Barrī said: the morphological analysis that al-Jawharī gave for this word, tracing it back to tābūwah, is a faulty analysis. He said: the correct [approach] is to mention it under the entry t-b-t, since its tāʾ is an original radical letter, its pattern being fāʿūl, like ʿāqūl and ḥāṭūm; and pausing on it with tāʾ is [the practice] in most dialects, while whoever pauses on it with hāʾ has substituted it for the tāʾ — just as [hāʾ] is substituted [for tāʾ] in al-Furāt when one pauses on it with hāʾ, even though the tāʾ of al-Furāt is not a feminine tāʾ but rather an original radical letter of the word itself. Abū Bakr ibn Mujāhid said: al-tābūt with tāʾ is the reading of all the [Qurʾān] reciters, while the dialect of the Anṣār is al-tābūwah with hāʾ.