blink of an eye vs jiffy

blink of an eye and jiffy both are nouns.

Word	Noun	Adjective	Verb	Adverb
blink of an eye	Yes	No	No	No
jiffy	Yes	No	No	No

As nouns, blink of an eye and jiffy are synonyms defined as:

blink of an eye and jiffy: a very short time (as the time it takes the eye to blink or the heart to beat)

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

blink of an eye (noun)	jiffy (noun)
a very short time (as the time it takes the eye to blink or the heart to beat)	a very short time (as the time it takes the eye to blink or the heart to beat)