sick vs excrete

sick is a noun but excrete is not a noun.

Word	Noun	Adjective	Verb	Adverb
sick	Yes	Yes	Yes	No
excrete	No	No	Yes	No

As verbs, excrete is a hypernym of sick; that is, excrete is a word with a broader meaning than sick:

Other hypernyms of sick include egest, eliminate, pass.

sick (noun)	excrete (noun)
people who are sick

sick (adjective)	excrete (adjective)
affected by an impairment of normal physical or mental function
shockingly repellent; inspiring horror
having a strong distaste from surfeit
affected with madness or insanity
deeply affected by a strong feeling
(of light) lacking in intensity or brightness; dim or feeble
feeling nausea; feeling about to vomit

sick (verb)	excrete (verb)
eject the contents of the stomach through the mouth	eliminate from the body