cave in

Verb

cave in (third-person singular simple present caves in, present participle caving in, simple past and past participle caved in)

1. (intransitive) To collapse inward or downward.
   • The roof caved in under the weight of the snow.
   • It was to assist in the filling-in of the tunnel on the disused Patricroft-Clifton Junction line, which was the scene of a disaster in 1953 when part, below some houses in Swinton, caved in.1955 June, “Notes and News: Locomotive Notes: London Midland Region”, in Railway Magazine, page 439

   Synonyms:

   cave, break, fall in, give way

2. (transitive) To cause to collapse inward or downward.
   • He caved in the side of the barrel with a single well-placed kick.

   Synonyms:

   break, crush, stave, stave in

3. (figuratively, intransitive) To relent; to grant approval against one's initial will.
   • After he asked me a few times, I finally caved in and had a slice of cake.
   • Eventually the NUR overplayed its hands with an all-out strike. And when Peter Parker, the then-chairman of BR, who was well regarded among his staff, called their bluff by threatening to close down the entire network, they caved in.2022 December 14, Christian Wolmar, “Productivity should play no part in pay negotiations”, in RAIL, number 972, page 46

   Synonyms:

   cave, assent, give in, give up, relinquish, yield, comply, acquiesce