crier vs bellower

crier and bellower both are nouns.

Word	Noun	Adjective	Verb	Adverb
crier	Yes	No	No	No
bellower	Yes	No	No	No

As nouns, bellower is a hypernym of crier; that is, bellower is a word with a broader meaning than crier:

Other hypernyms of crier include hawker, packman, peddler, pedlar, pitchman, bawler, roarer, screamer, screecher, shouter, yeller.

crier (noun)	bellower (noun)
(formerly) an official who made public announcements	someone who communicates vocally in a very loud voice
a person who weeps
a peddler who shouts to advertise the goods he sells