key fob vs keyfob

key fob and keyfob both are nouns.

Word	Noun	Adjective	Verb	Adverb
key fob	Yes	No	No	No
keyfob	Yes	No	No	No

As nouns, key fob and keyfob are synonyms defined as:

key fob and keyfob: A small object fastened to a key chain or key ring and designed to be comfortably grasped.

key fob (noun)	keyfob (noun)
A small object fastened to a key chain or key ring and designed to be comfortably grasped.	A small object fastened to a key chain or key ring and designed to be comfortably grasped.