noun: Military in origin, an official recognition or commendation for good work that is recorded in one's personnel file, specifically one that is a positive influence in a subsequent pay raise or promotion.
"Jones wasn't HR's choice for the new department manager, but the attaboys he got from the customer for that last project convinced the VP to lean on the Personnel weenies on his behalf"
A congratulatory phrase uttered from a woman to a man during sexual intercourse. In most cases, the woman is acting for an audience (ie. in-person, recorded, taped).
1. I thought she was enjoying herself but I wasn't sure until she screamed, "Attaboy". Then everyone in the room knew how she really felt.
2. "You like that baby?" - Man
"It feels so good... Attaboy!" - Woman
"Did she just say Attaboy?" - Third party viewer/listener.