forty winks vs short sleep

forty winks and short sleep both are nouns.

Word	Noun	Adjective	Verb	Adverb
forty winks	Yes	No	No	No
short sleep	Yes	No	No	No

As nouns, forty winks and short sleep are synonyms defined as:

forty winks and short sleep: sleeping for a short period of time (usually not in bed)

Other synonyms of forty winks include catnap, light sleep, nap, snooze.

forty winks (noun)	short sleep (noun)
sleeping for a short period of time (usually not in bed)	sleeping for a short period of time (usually not in bed)