lizard vs varan

lizard and varan both are nouns.

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

As nouns, varan is a hyponym of lizard; that is, varan is a word with a more specific, narrower meaning than lizard:

lizard: relatively long-bodied reptile with usually two pairs of legs and a tapering tail
varan: any of various large tropical carnivorous lizards of Africa and Asia and Australia; fabled to warn of crocodiles

lizard (noun)	varan (noun)
relatively long-bodied reptile with usually two pairs of legs and a tapering tail	any of various large tropical carnivorous lizards of Africa and Asia and Australia; fabled to warn of crocodiles
a man who idles about in the lounges of hotels and bars in search of women who would support him