Main Entry: ni·sus

Pronunciation: \ˈnī-səs\

Function: noun

Inflected Form(s): plural ni·sus \-səs, -ˌsüs\

Etymology: Latin, from niti to lean, rely, strive; akin to Latin nictare to wink — more at connive

Date: 1699

: a mental or physical effort to attain an end : a perfective urge or endeavor