a person who points out someone to be murdered, robbed, etc.
Origin of finger man
An Americanism dating back to 1925–30
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for finger man
Even if Nast were finger-man for a bandit gang he would get nothing except clothes and ordinary, easily replaced tools.The Golden Skull|John Blaine