field of study vs bailiwick

field of study and bailiwick both are nouns.

Word	Noun	Adjective	Verb	Adverb
field of study	Yes	No	No	No
bailiwick	Yes	No	No	No

As nouns, field of study and bailiwick are synonyms defined as:

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

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