संस्‍कृतशब्‍दकोशः

निस्

चूमना

to kiss

Monier–Williams

निस् — {nís} ind. out, forth, away &c. (rarely used as an independent word [e.g. vi, 18, 3 ; vii, 115, 3 ; xvi, 2, 1], but mostly as a prefix to verbs and their derivatives [cf. {niḥ-} √{kṣi} &c. below], or to nouns not immediately connected with verbs, in which case it has the sense, out of', away from' [cf. {nirvana}, {niṣ-kauśāmbi} &c.] or that of a privative or negative adverb= 3. {a}, without', destitute of', 'free from', un-' [cf. {nir-artha}, {nir-mala} &c.], or that of a strengthening particle 'thoroughly', entirely', 'very' [cf. {nih-śūnya}, {niṣ-kevala}, {nir-muṇḍa}]##it is liable to be changed to {niḥ}, {niś}, {niṣ}, and {niṣ} and {nī}##and below).

निस् — {nis} p. 543, col. 2