인정각이다 means "It is the situation that we/I need to admit" 인정 means "acknowledgment,recognition, approval" 각 literally means "angle" -각 is recently used as the meaning of -를 해야할 상황(the situation that someone needs to do something)

인정 means agree '인정agree' + '각' It is a slang for teenagers. You ask someone to agree with his words. '각' is used in various situations that you see chance of sth or feel like doing sth. ex) A: 인정각이냐? Do you agree? B: 어 인정(or 노인정, which means I do not agree) Yes I agree. 오늘 결식각이냐? Is it good to skip meal?(when the school meal is too bad to eat) 킬각 Chance to kill someone(used in game chatting) 각이 안 나오네 I don't see any opportunity.