가리다 is covering something so it can't be seen: 이마를 빽빽하게 가리는 앞머리 (a fringe covering the forehead completely), 형 카메라를 그렇게 가려? (are you really blocking the camera like that?), 얼굴 빨개져서 이렇게 가리고 있다가. A separate set phrase, 낯을 가리다, means being shy with people you don't know — 낯을 진짜 심하게 가려요, he's terribly shy around strangers — and two lines use it.