During a match, you will sometimes get medals or 'honors'. As you progress through the single player game, you accumulate these. When you get one, a small version flashes over your head for about 2 seconds in the game. They are also displayed at the end of the match.
Accuracy
Completing a match with better than 50% accuracy
Excellent
Fragging an opponent within 4 seconds of a previous frag
Frags
Awarded after each 100 frags earned
Gauntlet
Punching someone to death.
Impressive
Awarded for every TWO successive railgun shots
Victory
This is winning a game without being fragged (or suicide)
Screenshots Courtesy of id software and Stomped. All images and names © id software.