adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
creakily; with a creaking sound
Describes a harsh, grating sound, often from something tight or strained. Used adverbially, often with と or as a する-verb.
古い扉がギチギチと音を立てて開いた。
The old door opened with a creaking sound.
椅子がギチギチして、座るたびにきしむ。
The chair is creaky and squeaks every time I sit on it.
na-adjective
tight; cramped; with no room to spare
Describes a state where things are packed tightly or fit exactly with no extra space. Used as a na-adjective.
この箱はギチギチに詰め込まれている。
This box is packed tight with no room to spare.
スケジュールがギチギチで、休む暇がない。
My schedule is so tight that I have no time to rest.