Definitions for kick in
set in, kick in(verb)
enter a particular state
"Laziness set in"; "After a few moments, the effects of the drug kicked in"
contribute, give, chip in, kick in(verb)
contribute to some cause
"I gave at the office"
kick in, kick down(verb)
"kick in the doors"
Kernerman English Learner's Dictionary
to start to have an effect
The painkillers haven't kicked in yet.
To kick or strike so as to cause the object struck to collapse or fall inwards.
To start or connect suddenly.
To contribute, especially to a collection of money.