Lewis Short
strēnŭĭtas (noun F) : strenuus
* 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.
Charlton T. Lewis, Charles Short, A Latin Dictionary