niccaṁ

adjective constant, continuous, permanent DN.iii.31; SN.i.142; SN.ii.109, SN.ii.198; SN.iv.24 sq., SN.iv.45, SN.iv.63; AN.ii.33, AN.ii.52 AN.v.210; Pts.ii.80; Vb.335, Vb.426. In chain of synonyms nicca dhuva sassata avipariṇāmadhamma DN.i.21; SN.iii.144, SN.iii.147; see below anicca, -nt. adv. niccaṃ perpetually, constantly, always (syn. sadā) MN.i.326 MN.iii.271; Snp.69, Snp.220, Snp.336; Dhp.23, Dhp.109, Dhp.206, Dhp.293; Ja.i.290 Ja.iii.26, Ja.iii.190; Cnd.345 (= dhuvakālaṃ); Pv-a.32, Pv-a.55, Pv-a.134. Far more freq. as anicca (adj.; aniccaṃ nt. n.) unstable impermanent, inconstant; (nt.) evanescence, inconstancy, impermanence
■ The emphatic assertion of impermanence (continuous change of condition) is a prominent axiom of the Dhamma, & the realization of the evanescent character of all things mental or material is one of the primary conditions of attaining right knowledge (: anicca-saññaṃ manasikaroti to ponder over the idea of impermanence SN.ii.47; SN.iii.155; SN.v.132; Pts.ii.48 sq., Pts.ii.100; Pv-a.62 etc
■ kāye anicc’ ânupassin realizing the impermanence of the body (together with vayânupassin & nirodha˚) SN.iv.211; SN.v.324, SN.v.345; Pts.ii.37, Pts.ii.45 sq., Pts.ii.241 sq. See anupassanā). In this import anicca occurs in many combinations of similar terms all characterising change, its consequences & its meaning esp. in the famous triad “aniccaṃ dukkhaṃ anattā” (see dukkha ii.2), e.g. SN.iii.41, SN.iii.67, SN.iii.180; SN.iv.28 (sabbaṃ), SN.iv.85 sq., SN.iv.106 sq.; SN.iv.133 sq. Thus anicca addhuva appāyuka cavanadhamma DN.i.21. anicca + dukkha SN.ii.53 (yad aniccaṃ taṃ dukkhaṃ); SN.iv.28, SN.iv.31, SN.v.345; AN.iv.52 (anicce dukkhasaññā); MN.i.500 (+ roga etc.); Cnd.214 (id. cp roga). anicca dukkha vipariṇāmadhamma (of kāmā DN.i.36. aniccasaññī anattasaññī AN.iv.353; etc. Opposed to this ever-fluctuating impermanence is Nibbāna (q.v.), which is therefore marked with the attributes of constancy & stableness (cp. dhuva, sassata amata, vipariṇāma)
■ See further for ref. SN.ii.244 sq (saḷāyatanaṃ a.), SN.ii.248 (dhātuyo); SN.iii.102 (rūpa etc.), SN.iv.131