wink

Concise Oxford English Dictionary © 2008 Oxford University Press:
wink/wɪŋk/

▶verb

• 1 close and open one eye quickly, typically as a signal of affection or greeting or to convey a message.

• 2 shine or flash intermittently.

• 3 (wink at) pretend not to notice (something bad).

▶noun an act of winking.

– phrases
as easy as winking informal very easy or easily.
in the wink of an eye (or in a wink) very quickly.
not sleep (or get) a wink (or not get a wink of sleep) not sleep at all.

– derivatives
winker noun.

– origin OE wincian ‘close the eyes’, of Gmc origin; rel. to wince1.