guardian spirit vs guardian angel

guardian spirit and guardian angel both are nouns.

Word	Noun	Adjective	Verb	Adverb
guardian spirit	Yes	No	No	No
guardian angel	Yes	No	No	No

As nouns, guardian spirit and guardian angel are synonyms defined as:

guardian spirit and guardian angel: an angel believed to have special affection for a particular individual

guardian spirit (noun)	guardian angel (noun)
an angel believed to have special affection for a particular individual	an angel believed to have special affection for a particular individual