lepidopteran vs insect

lepidopteran and insect both are nouns.

Word	Noun	Adjective	Verb	Adverb
lepidopteran	Yes	No	No	No
insect	Yes	No	No	No

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

lepidopteran: insect that in the adult state has four wings more or less covered with tiny scales
insect: small air-breathing arthropod

lepidopteran (noun)	insect (noun)
insect that in the adult state has four wings more or less covered with tiny scales	small air-breathing arthropod
	a person who has a nasty or unethical character undeserving of respect