roaster vs baster

roaster and baster both are nouns.

Word	Noun	Adjective	Verb	Adverb
roaster	Yes	No	No	No
baster	Yes	No	No	No

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

roaster (noun)	baster (noun)
a special cooking pan for roasting	a tube with a rubber bulb used to take up and release melted fat or gravy in order to moisten roasting meat
flesh of a large young chicken over 3 1/2 lb suitable for roasting	a sewer who fastens a garment with long loose stitches
a cook who roasts food	a cook who bastes roasting meat with melted fat or gravy
a harsh or humorous critic (sometimes intended as a facetious compliment)