sick vs sick of

sick is a noun but sick of is not a noun.

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

As adjectives, sick and sick of are synonyms defined as:

Other synonyms of sick include disgusted, fed up, tired of.

sick (noun)	sick of (noun)
people who are sick

sick (adjective)	sick of (adjective)
affected by an impairment of normal physical or mental function	having a strong distaste from surfeit
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)	sick of (verb)
eject the contents of the stomach through the mouth