sickness benefit vs sick benefit

sickness benefit and sick benefit both are nouns.

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

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

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

sickness benefit (noun)	sick 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