anise oil vs oil of anise

anise oil and oil of anise both are nouns.

Word	Noun	Adjective	Verb	Adverb
anise oil	Yes	No	No	No
oil of anise	Yes	No	No	No

As nouns, anise oil and oil of anise are synonyms defined as:

anise oil and oil of anise: an essential oil extracted from the seeds of Pimpinella anisum (aniseed), having a pungent liquorice-like smell.

Other synonyms of anise oil include aniseed oil.

anise oil (noun)	oil of anise (noun)
an essential oil extracted from the seeds of Pimpinella anisum (aniseed), having a pungent liquorice-like smell.	an essential oil extracted from the seeds of Pimpinella anisum (aniseed), having a pungent liquorice-like smell.