split second vs wink

split second and wink both are nouns.

Word	Noun	Adjective	Verb	Adverb
split second	Yes	No	No	No
wink	Yes	No	Yes	No

As nouns, split second and wink are synonyms defined as:

split second and wink: a very short time (as the time it takes the eye to blink or the heart to beat)

Other synonyms of split second include blink of an eye, flash, heartbeat, instant, jiffy, New York minute, trice, twinkling.

split second (noun)	wink (noun)
a very short time (as the time it takes the eye to blink or the heart to beat)	a reflex that closes and opens the eyes rapidly
	closing one eye quickly as a signal
	a very short time (as the time it takes the eye to blink or the heart to beat)

split second (verb)	wink (verb)
	briefly shut the eyes
	keep back by blinking
	signal by winking
	gleam or glow intermittently