Parkinsonism vs Parkinson's

Parkinsonism and Parkinson's both are nouns.

Word	Noun	Adjective	Verb	Adverb
Parkinsonism	Yes	No	No	No
Parkinson's	Yes	No	No	No

As nouns, Parkinsonism and Parkinson's are synonyms defined as:

Parkinsonism and Parkinson's: a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination

Other synonyms of Parkinsonism include paralysis agitans, Parkinson's disease, Parkinson's syndrome, shaking palsy.

Parkinsonism (noun)	Parkinson's (noun)
a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination	a degenerative disorder of the central nervous system characterized by tremor and impaired muscular coordination