liberal arts vs field of study

liberal arts and field of study both are nouns.

Word	Noun	Adjective	Verb	Adverb
liberal arts	Yes	No	No	No
field of study	Yes	No	No	No

As nouns, field of study is a hypernym of liberal arts; that is, field of study is a word with a broader meaning than liberal arts:

liberal arts: studies intended to provide general knowledge and intellectual skills (rather than occupational or professional skills)
field of study: a branch of knowledge

Other hypernyms of liberal arts include bailiwick, discipline, field, study, subject, subject area, subject field.

liberal arts (noun)	field of study (noun)
studies intended to provide general knowledge and intellectual skills (rather than occupational or professional skills)	a branch of knowledge