1) Agnew, once 2) Agnew, to Nixon 3) Al, now 4) Al, to Bill 5) Alben Barkley sobriquet 6) Albert Gore for one 7) Backup for a prez 8) Backup to a prez 9) Barkley nickname 10) Barkley sobriquet 11) Barkley was one 12) Barkley 13) Biden 14) Bush 41 was one 15) Cheney 16) Dick Cheney 17) Dick, to Dubya 1) Asst 2) Exec 
Veep is slang for a very important person.