angel vs backer

angel and backer both are nouns.

Word	Noun	Adjective	Verb	Adverb
angel	Yes	No	No	No
backer	Yes	No	No	No

As nouns, angel and backer are synonyms defined as:

angel and backer: someone who provides financial support for some venture

angel (noun)	backer (noun)
spiritual being attendant upon God	someone who provides financial support for some venture
someone who provides financial support for some venture
person of exceptional holiness