strenuitas

Ζῆν οὐκ ἄξιος, ὅτῳ μηδὲ εἷς ἐστι χρηστὸς φίλος → Life is not worth living if you do not have at least one friend.

Latin > English (Lewis & Short)

strēnŭĭtas: ātis, f. strenuus,
I nimbleness, briskness, vivacity, activity (very rare; perh. only in the two foll. passages): ab strenuitate et nobilitate strenui et nobiles, Varr. L. L. 8, § 15 Müll.: strenuitas antiqua manet, Ov. M. 9, 320.

strēnŭĭtās, ātis, f. (strenuus), activité, diligence, entrain : Varro L. 8, 15 ; Ov. M. 9, 320.