sick benefit vs sickness benefit

sick benefit and sickness benefit both are nouns.

Word	Noun	Adjective	Verb	Adverb
sick benefit	Yes	No	No	No
sickness benefit	Yes	No	No	No

As nouns, sick benefit and sickness benefit are synonyms defined as:

sick benefit and sickness benefit: money paid (by the government) to someone who is too ill to work

sick benefit (noun)	sickness benefit (noun)
money paid (by the government) to someone who is too ill to work	money paid (by the government) to someone who is too ill to work