frock vs sundress

frock and sundress both are nouns.

Word	Noun	Adjective	Verb	Adverb
frock	Yes	No	Yes	No
sundress	Yes	No	No	No

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

frock: a one-piece garment for a woman; has skirt and bodice
sundress: a light loose sleeveless summer dress with a wide neckline and thin shoulder straps that expose the arms and shoulders

frock (noun)	sundress (noun)
a one-piece garment for a woman; has skirt and bodice	a light loose sleeveless summer dress with a wide neckline and thin shoulder straps that expose the arms and shoulders
a habit worn by clerics
a long, loose outer garment

frock (verb)	sundress (verb)
put a frock on