crier vs screecher

crier and screecher both are nouns.

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

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

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

crier (noun)	screecher (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