꾸무묵 doesn't exist as far as I know, but there is 꾸우욱 which might look like 꾸무묵 if you don't look carefully. 꾸우욱's standard form is 꾹 or 꾸욱 (꼭 and 꼬옥 are also similar), but people sometimes lengthen it to 꾸우욱. It is an onomatopoeia describing: 1) pushing or pressing something down firmly, 2) enduring pain or trying to hold one's emotion in, 3) an object being stuck or wedged hard in something, or a person staying put in a place. - 나는 손으로 초인종을 꾸욱 눌렀다 = I pressed the doorbell firmly with my hand. - 아파도 꾹 참아라 = It might hurt but try and endure it. - 일주일 동안 집에 꾹 틀어박혀 있었다 = I stayed put in the house for one whole week.