움직이는 게 is colloquial form of "움직이는 것이" 움직이는 is present tense modifier form of 움직이다 움직이다 means "to move" 것 means "thing" 움직이는 것 means "something which is moving/the action of moving" 이 is subject particle ex) 사람들이 움직이는 게 보인다 I see that people is moving. 힙합 음악은 리듬을 타면서 움직이는 게 정말 중요해요. For hip-hop music, it's very important to be able to move to the groove. 게 also means "crab" The other possible meaning is "a moving crab"