SCREECHIEST
Scrabble letter values: S1C3R1E1E1C3H4I1E1S1T1 = 18
Definition
SCREECHIEST is the superlative of SCREECHY.
adjective SCREECHY: having or making a high-pitched sound such as that made by a mouse or a rusty hinge.
Synonyms of SCREECHY: screaky, squeaking, squeaky, squealing