bailiwick vs subject area

bailiwick and subject area both are nouns.

Word	Noun	Adjective	Verb	Adverb
bailiwick	Yes	No	No	No
subject area	Yes	No	No	No

As nouns, bailiwick and subject area are synonyms defined as:

Other synonyms of bailiwick include discipline, field, field of study, study, subject, subject field.

bailiwick (noun)	subject area (noun)
a branch of knowledge	a branch of knowledge
the area over which a bailiff has jurisdiction