zizz vs light sleep

zizz and light sleep both are nouns.

Word	Noun	Adjective	Verb	Adverb
zizz	Yes	No	No	No
light sleep	Yes	No	No	No

As nouns, light sleep is a hypernym of zizz; that is, light sleep is a word with a broader meaning than zizz:

Other hypernyms of zizz include catnap, forty winks, nap, short sleep, snooze.

zizz (noun)	light sleep (noun)
a nap	sleeping for a short period of time (usually not in bed)
a buzzing or whizzing sound