Parkinson's disease vs Parkinsonism

Parkinson's disease and Parkinsonism both are nouns.

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

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

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

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

Parkinson's disease (noun)	Parkinsonism (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