baster vs roaster

baster and roaster both are nouns.

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

As nouns, roaster is a hypernym of baster; that is, roaster is a word with a broader meaning than baster:

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