kick in
verb
RareNot in standard dictionaries
1
To kick or strike so as to cause the object struck to collapse or fall inwards.
2
To kick or strike (a person); to beat up.
3
To start, connect, or take effect, especially in a sudden way; to begin functioning.
4
To join or begin.
5
To contribute, especially to a collection of money; to hand over.
6
To die; to give up on something.
#slang