croak vs give-up the ghost

croak is a noun but give-up the ghost is not a noun.

Word	Noun	Adjective	Verb	Adverb
croak	Yes	No	Yes	No
give-up the ghost	No	No	Yes	No

As verbs, croak and give-up the ghost are synonyms defined as:

croak and give-up the ghost: pass from physical life and lose all bodily attributes and functions necessary to sustain life

croak (noun)	give-up the ghost (noun)
a harsh hoarse utterance (as of a frog)

croak (verb)	give-up the ghost (verb)
pass from physical life and lose all bodily attributes and functions necessary to sustain life	pass from physical life and lose all bodily attributes and functions necessary to sustain life
make complaining remarks or noises under one's breath
utter a hoarse sound, like a raven