kick in

present singular third person kicks in · participle present kicking in · participle past kicked in · past kicked in

1. To kick; to collapse or break by kicking.
   1. transitiveTo kick or strike so as to cause the object struck to collapse or fall inwards.

      You touch me again, I swear I’ll kick your teeth in.

      1 more example

      Upon hearing residents in the burning house, the passerby kicked in the front door and yelled to those inside.

   2. slangtransitiveTo kick or strike (a person); to beat up.
2. To begin, contribute or join in on.
   1. idiomaticintransitiveTo start, connect, or take effect, especially in a sudden way; to begin functioning.

      You have to push the switch hard to get the heater to kick in.

      3 more examples

      I took my medication an hour ago, and it hasn't kicked in yet.

      People expect women [when they give birth] to have this instinct that kicks in.

      2013, Richard Linklater, Julie Delpy, Ethan Hawke, Before Midnight (motion picture), Julie Delpy (actor)

      Once the wet kicks in up north, you can be stranded for months waiting for swollen rivers to subside to a crossable depth[.]

      2005, Sean Dooley, The Big Twitch, Sydney: Allen and Unwin, page 289

   2. slangTo join or begin.

      You should kick in on the work.

      1 more example

      The rhythm section will kick in after that point.

   3. idiomaticintransitivetransitiveTo contribute, especially to a collection of money; to hand over.

      This is a worthy charity, so everyone should kick in.

      1 more example

      For the year-end party, we're asking each employee to kick in twenty dollars.

3. idiomaticTo die; to give up on something.

   The business is going to kick in most likely.