moth vs lepidopterous insect

moth and lepidopterous insect both are nouns.

Word	Noun	Adjective	Verb	Adverb
moth	Yes	No	No	No
lepidopterous insect	Yes	No	No	No

As nouns, lepidopterous insect is a hypernym of moth; that is, lepidopterous insect is a word with a broader meaning than moth:

moth: typically crepuscular or nocturnal insect having a stout body and feathery or hairlike antennae
lepidopterous insect: insect that in the adult state has four wings more or less covered with tiny scales

Other hypernyms of moth include lepidopteran, lepidopteron.

moth (noun)	lepidopterous insect (noun)
typically crepuscular or nocturnal insect having a stout body and feathery or hairlike antennae	insect that in the adult state has four wings more or less covered with tiny scales