1) Buckled 2) Fell to persuasion 3) Finally said yes 4) Gave in 5) Gave in under pressure 6) Gave in, finally 7) Gave in, so to speak 8) Hollowed 9) Hollowed out 10) Hollowed; undermined 11) Spelunked 12) Submitted 13) Succumbed to duress 14) Surrendered 15) Went spelunking 16) Yielded 17) Yielded to pressure 1) Gave in 
• (imp. & p. p.) of Cave