Charlton T. Lewis, Charles Short, A Latin Dictionary

I.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.