food poisoning vs unwellness

food poisoning and unwellness both are nouns.

Word	Noun	Adjective	Verb	Adverb
food poisoning	Yes	No	No	No
unwellness	Yes	No	No	No

As nouns, unwellness is a hypernym of food poisoning; that is, unwellness is a word with a broader meaning than food poisoning:

food poisoning: illness caused by poisonous or contaminated food
unwellness: impairment of normal physiological function affecting part or all of an organism

Other hypernyms of food poisoning include illness, malady, sickness.

food poisoning (noun)	unwellness (noun)
illness caused by poisonous or contaminated food	impairment of normal physiological function affecting part or all of an organism