fellowship vs companionship

fellowship and companionship both are nouns.

Word	Noun	Adjective	Verb	Adverb
fellowship	Yes	No	No	No
companionship	Yes	No	No	No

As nouns, fellowship and companionship are synonyms defined as:

Other synonyms of fellowship include company, society.

fellowship (noun)	companionship (noun)
an association of people who share common beliefs or activities	the state of being with someone
money granted (by a university or foundation or other agency) for advanced study or research
the state of being with someone