Adverb (fukushi), Adverb taking the 'to' particle
with a (sharp) creak; with a squeak; with a screech
Onomatopoeic or mimetic word
私が我慢できないことは、黒板でキーキーとチョークが音を立てることだ。What I can't bear is the sound of chalk squeaking on a chalkboard.
Also written キイキイ、キィキィ、きーきー、きいきい、きぃきぃ