ليسIbn Fāris has no entry for this root in the material supplied; laysa is a defective … (root lys)

لَيْسَ

1. لَيْسَ a word denoting negation: (S, A, K:) it is a verb in the pret. tense, (S, A, K, Mughnee,) having no other tense, (Sb, S, M, Msb, Mughnee,) nor a part. n. nor an inf. n.; (Sb, M, Msb; *) of the measure فَعِلَ; (Mughnee;) originally لَيِسَ, from which it is contracted by the suppression of a vowel, (Sb, * S, M, * K, Mughnee, *) being found difficult of pronunciation, (S,) [i. e.,] to render it easy to pronounce, (K,) like عَلْمَ for عَلِمَ, (Sb, M,) the ى not being changed into ا (Sb, S, M) because it is imperfectly inflected, being used in the pret. form for the present, (S,) [i. e.,] because it has no future, nor part. n., nor inf. n., nor derivation, wherefore, not being perfectly inflected like its coordinates, it is made like that which is not a verb, as لَيْتَ: (Sb, M:) what shows it to be a verb, (S, Mughnee,) not a particle occupying the place of مَا, as Ibn-Es-Sarráj and some others after him have asserted, (Mughnee,) though not perfectly inflected like [other] verbs, (S,) is their saying لَسْتَ and لَسْتُمَا (S, Mughnee) and لَسْتُمْ (S) and لَيْسَا and لَيْسُوا and لَيْسَتْ [&c.], (Mughnee,) like as they say ضَرَبْتَ and ضَرَبْتُمَا and ضَرَبْتُمْ [&c.]: (S:) we have not determined its measure to be فَعَلَ, because this is not contracted; nor فَعُلَ, because there is no verb of this measure with ى for its medial radical letter, except هَيُؤَ; but لُسْتَ has been heard; so, accord. to this form, it may be like هَيُؤَ: (Mughnee:) the Benoo-Dabbeh say لُسْتُ and لُسْنَا in the sense of لَسْتُ and لَسْنَا; and some of them say لِسْتُ: (TA, art. لوس:) but Sb says, that the Arabs did not say لِسْتَ, like as they said خِفْتَ, because ليس is not perfectly inflected like [other] verbs. (M.) [There is also another opinion respecting its origin, which will be mentioned in the course of this article.] It [is generally a particular (not a universal) negative, and] denotes the negation of a thing at the present time; (M, Mughnee;) [i. e.] it denotes [thus] the negation of its predicate: (Msb:) and has the same government as the verbكَانَ and its coordinates; (S;) governing the subject in the nom., and the predicate in the accus.: (S, Mughnee:) as when you say, لَيْسَ زَيْدٌ قَائِمًا [Zeyd is not a person standing]: (Msb:) and by means of the context, it denotes the negation of a thing at a time not the present; as in the saying of El-Aashà [respecting Mohammad], [He has bounties the bestowing of which is not on alternate days; and the giving of to-day will not be a preventer of it to-morrow]; and [sometimes when it is followed by a verb, as] in the saying, لَيْسَ خَلَقَ ٱللّٰهُ مِثْلَهُ [God has not created the like of him, or it.] (Mughnee.) But it differs from its coordinates in that the prep. بِ may be prefixed to its predicate: as in the saying, لَيْسَ زَيْدٌ بِمُنْطَلِقٍ [Zeyd is not going away]; the ب being a means of the verb's being trans., and also corroborative of the negation: and one may optionally not introduce it, because one may do without the corroborative, and because some verbs are trans. sometimes by means of a prep. and sometimes without a prep., as اِشْتَقْتُكَ and اِشْتَقْتُ إِلَيْكَ. (S.) It also differs from its coordinates in that its predicate may not be put before it: for you may say مُحْسِنًا كَانَ زَيْدٌ, but not مُحْسِنًا لَيْسَ زَيْدٌ: (S:) or some allow this latter; but others disallow it. (Ibn- 'Akeel on the Alfeeyeh, section on كان and its coordinates.) It is also used as an exceptive particle, (S, M, Mughnee,) in the place of إِلَّا; (S, Mughnee;) in which case [also] its subject [which is understood] is in the nom. case, and its predicate in the accus.: (S:) you say, جَآءَنِى القَوْمُ لَيْسَ زَيْدًا [The company of men came to me, except Zeyd]; as though you said, لَيْسَ الجَائِى زَيْدًا. (S, M: but in the latter, instead of جاءنى, we find أَتَى; and instead of الجائى, we find الآتِى.) You may also say, جَآءَنِى القَوْمُ لَيْسَكَ [The company of men came to me, excepting thee]; but the separate pronoun, إِيَّاكَ, is here better. (S.) When the predicate after it is connected with إِلَّا, as in the ex. here next following, Benoo-Temeem make it in the nom. case: thus they say, لَيْسَ الطِّيبُ إِلَّا المِسْكُ [It is not perfume, except musk; meaning, nothing is perfume except musk]: which has been resolved is several ways; some holding الطيب to be the subject of ليس: but its being peculiar to the dial. of Temeem refutes the explanations here referred to: some, again, hold ليس to be here used as a particle; and so in the saying لَيْسَ خَلَقَ ٱللّٰهُ مِثْلَهُ, mentioned above. (Mughnee.) Sometimes it is used in the sense of لَا التَّبْرِئَةِ [the لا which denies in a general manner to the uttermost, i. e., universally, or totally]; as is said in the K, except that in all the copies thereof we find وَإِنَّمَا put by mistake for وَرُبَّمَا: (TA:) [so in the saying in the Kur, ii. 194, لَيْسَ عَلَيْكُمْ جُنَاحٌ, which is the same as لَا جُنَاحَ عَلَيْكُمْ in verse 235 of the same chapter, meaning, There shall be no crime, or sin, chargeable upon you]. Sometimes, also, it is used as a connective particle, (Mughnee,) in the sense of لا so used: (TA:) as in the saying [of a poet], [Where is the place of flight when God is the pursuer, and El-Ashram (meaning Abrahah) is the overcome, not the overcomer?]: which has been resolved by supposing الغالب to be the subject of ليس, and the predicate to be suppressed; the latter being said by Ibn-Málik to be an annexed pronoun referring to El-Ashram; so that the meaning is لَيْسَهُ الغَالِبُ [the overcomer is not he]. (Mughnee.) It is said (M, K) by Fr, (M,) and also by Kh, (TA,) that the original of لَيْسَ is لَا أَيْسَ; (M, K [in the latter of which I read أَوْ أَصْلُهُ, as in several copies of the K, or rather أَوْ أَصْلُهَا, as corrected in the TA, instead of أَوْ مَعْنَاهُ, the reading in the CK];) and this, says Fr, is shown by the saying, جِئْ بِهِ مِنْ أَيْسَ وَلَيْسَ, i. e., [Bring thou him, or it,] from where he, or it, is, and is not: (M:) or اِيتِنِى مِنْ حَيْثُ أَيْسَ وَلَيْسَ i. e., [Come thou to me, or probably, the right reading is اِيتِنِى بِهِ bring thou to me him, or it, (as I find in a copy of the K, in which به has been added in red ink, and in the A I find إِيتِ بِهِ,)] from where he, or it, is, and he, or it, is not: (K:) or the meaning is, مِنع حَيْثُ لَا وُجْدَ [from where there is no finding; or no being found, or no existence; or no power, or ability]: (K, * TA:) or أَيْسَ means مَوْجُودٌ [found, or existing], and لَا أَيْسَ [means] لَا مَوْجُودٌ [not found, or not existing], and is contracted [into لَيْسَ]: (K:) [but the last rendering of ايس and لا ايس seems to be taken from an explanation, not literal, of another saying; مَا يَعْرِفُ أَيْسَ مِنْ لَيْسَ he knows not a thing existing from a thing not existing.] Aboo-'Alee relates, that Sb said, جِئْ بِهِ مِنْ حَيْثُ وَلَيْسَا [Bring thou him, or it, from where he, or it, is and is not]; meaning, وَلَيْسَ, the fet-hah of the س being made full in sound, on account of the pause. (M.) In the saying of a certain poet, [Wants have been forgotten as old things (so رُسَّت is explained in the M, as used here, in art. رس,) with Keys, since he ceases not to be addicted to the use of the word leysa], it is made by him a noun, and declined. (M.)