frighten vs fear

frighten is not a noun while fear is a noun.

Word	Noun	Adjective	Verb	Adverb
frighten	No	No	Yes	No
fear	Yes	No	Yes	No

frighten (noun)	fear (noun)
	an emotion experienced in anticipation of some specific pain or danger (usually accompanied by a desire to flee or fight)
	an anxious feeling
	a feeling of profound respect for someone or something

frighten (verb)	fear (verb)
cause fear in	be afraid or scared of; be frightened of
	regard with feelings of respect and reverence; consider hallowed or exalted or be in awe of
	be sorry; used to introduce an unpleasant statement
	be afraid or feel anxious or apprehensive about a possible or probable situation or event
	be uneasy or apprehensive about