coffin vs casket

coffin and casket both are nouns.

Word	Noun	Adjective	Verb	Adverb
coffin	Yes	No	Yes	No
casket	Yes	No	Yes	No

As nouns, coffin and casket are synonyms defined as:

coffin (noun)	casket (noun)
box in which a corpse is buried or cremated	small and often ornate box for holding jewels or other valuables
	box in which a corpse is buried or cremated

coffin (verb)	casket (verb)
place into a coffin	enclose in a casket