short form of "high cappin" which was used in the 80's to describe some one who lies about their social status or one who flaunt's arogantly brand new merchandise but is in debt. now-a-days its basically used to describe a liar but it still refers to he old meaning from time to time.
1)john-"he ain't got a slab
. he still drives his maw maw's car. he needs to stop all that cappin."
2)pete-"man, that boy still owes me 3g's and his out there cappin."
3)derrick-"quite cappin man, you did't call sherry cuz she just called me asking for you."