"to wink," 1822, from Medieval Latin nictitatus, past participle of nictitare, frequentative of Latin nictare "wink, blink, signal with the eyes," related to nicere "to beckon," from PIE root *kneigwh- "to blink, to draw together (the eyes or eyelids)," source also of Gothic hniewan, Old High German nigan "to bow, be inclined." Related: Nictitated; nictitating (1713). Earlier form was nictate (v.), 1690s, from Latin nictare.
"the act of winking," 1620s, from Latin nictationem (nominative nictatio), noun of action from past-participle stem of nictare "to wink, blink" (see nictitate). Alternative form nictitation is from 1784.
c. 1600, "shut one's eyes to something one does not like but cannot help," from Latin connivere, also conivere "to wink," hence, figuratively, "to wink at (a crime), be secretly privy," from assimilated form of com "with, together" (see con-) + base akin to nictare "to wink" (from PIE root *kneigwh-; see nictitate). From 1630s as "conceal knowledge (of a fault or crime of another); give silent encouragement to a culpable person." From 1797 as "be in secret complicity." Related: Connived; conniving.