friend vs ally

friend and ally both are nouns.

Word	Noun	Adjective	Verb	Adverb
friend	Yes	No	No	No
ally	Yes	No	Yes	No

As nouns, friend and ally are synonyms defined as:

friend (noun)	ally (noun)
a person you know well and regard with affection and trust	a friendly nation
a person with whom you are acquainted	an associate who provides cooperation or assistance
an associate who provides cooperation or assistance
a person who backs a politician or a team etc.

friend (verb)	ally (verb)
	become an ally or associate, as by a treaty or marriage