Nouns

(n)bellow, bellowing, holla, holler, hollering, hollo, holloa, roar, roaring, yowla very loud utterance (like the sound of an animal)“his bellow filled the hallway”
(n)hollow, hollera small valley between mountains“he built himself a cabin in a hollow high up in the Appalachians”

Verbs

(v)holler, holler outshout out“He hollered out to surrender our weapons”
(v)shout, shout out, cry, call, yell, scream, holler, hollo, squallutter a sudden loud cry“she cried with pain when the doctor inserted the needle”, “I yelled to her from the window but she couldn't hear me”
(v)gripe, bitch, grouse, crab, beef, squawk, bellyache, hollercomplain“What was he hollering about?”