nīsus (noun M) : nitor
* A pressing or resting upon or against, a pressure; a striving, exertion, labor, effort (mostly poet.; nixus in good prose, v. h. v.): pedetentim et sedato nisu, a tread, step, Pac. ap. Cic. Tusc. 2, 21, 48: pinnarum nisus inanis,a flight,Lucr. 6, 834; so, insolitos docuere nisus,Hor. C. 4, 4, 8: hic dea se primum rapido pulcherrima nisu Sistit,Verg. A. 11, 852: stat gravis Entellus nisuque immotus eodem, etc.,in the same posture,id. ib. 5, 437: hunc stirps Oceani maturis nisibus Aethra Edidit, pains, throes, labor of parturition (v. 2. nixus), Ov. F. 5, 171.—In prose: tamquam nisus evomentis adjuvaret,retchings,Tac. A. 12, 67: uti prospectus nisusque per saxa facilius foret,Sall. J. 94, 1 Dietsch: quae dubia nisu videbantur,id. ib. 94, 2 Dietsch: non pervenit nisu sed impetu,Quint. 8, 4, 9; 1, 12, 10.

nīsus, a, um, Part., from nitor.