lingerie vs nightgown

lingerie and nightgown both are nouns.

Word	Noun	Adjective	Verb	Adverb
lingerie	Yes	No	No	No
nightgown	Yes	No	No	No

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

lingerie: women's underwear and nightclothes
nightgown: lingerie consisting of a loose dress designed to be worn in bed by women

Other hyponyms of lingerie include gown, night-robe, nightdress, nightie, undies.

lingerie (noun)	nightgown (noun)
women's underwear and nightclothes	lingerie consisting of a loose dress designed to be worn in bed by women