lizard vs gigolo

lizard and gigolo both are nouns.

Word	Noun	Adjective	Verb	Adverb
lizard	Yes	No	No	No
gigolo	Yes	No	No	No

As nouns, gigolo is a hypernym of lizard; that is, gigolo is a word with a broader meaning than lizard:

lizard: a man who idles about in the lounges of hotels and bars in search of women who would support him
gigolo: a man who has sex with and is supported by a woman

lizard (noun)	gigolo (noun)
relatively long-bodied reptile with usually two pairs of legs and a tapering tail	a man who has sex with and is supported by a woman
a man who idles about in the lounges of hotels and bars in search of women who would support him