|Origin:||Probably from calve 'to cave in' (18-19 centuries), perhaps from Flemish inkalven; influenced by CAVE1|
cave inphrasal verb
if the top or sides of something cave in, they fall down or inwards
cave in on
The roof of the tunnel caved in on them.
to finally stop opposing something, especially because someone has persuaded or threatened you
cave in to
The chairman is expected to cave in to pressure from shareholders.