hollering vs holler

hollering and holler both are nouns.

Word	Noun	Adjective	Verb	Adverb
hollering	Yes	No	No	No
holler	Yes	No	Yes	No

As nouns, hollering and holler are synonyms defined as:

hollering and holler: a very loud utterance (like the sound of an animal)

Other synonyms of hollering include bellow, bellowing, holla, hollo, holloa, roar, roaring, yowl.

hollering (noun)	holler (noun)
a very loud utterance (like the sound of an animal)	a very loud utterance (like the sound of an animal)
	a small valley between mountains