maillot vs leotards

maillot and leotards both are nouns.

Word	Noun	Adjective	Verb	Adverb
maillot	Yes	No	No	No
leotards	Yes	No	No	No

As nouns, leotards is a hypernym of maillot; that is, leotards is a word with a broader meaning than maillot:

maillot: tights for dancers or gymnasts
leotards: skintight knit hose covering the body from the waist to the feet worn by acrobats and dancers and as stockings by women and girls

Other hypernyms of maillot include tights.

maillot (noun)	leotards (noun)
tights for dancers or gymnasts	skintight knit hose covering the body from the waist to the feet worn by acrobats and dancers and as stockings by women and girls
a woman's one-piece bathing suit