I had to copy / paste this in from my crossfit box's site today.  Words to live by...

Definition of a Clock Whore: Person who is so obsessed with beating the clock/others that they will prostitute themselves and sacrifice important and vital components of training such as range of motion, repetitions or other performance metrics for a ''better'' time.  These people actually miss the whole point of the training. The point of physical fitness training, from my perspective, is to improve oneself both physically and mentally, not necessarily in that order. The people who have taken the time clock or score beyond the extreme and compromised range of motion, number of repetitions, etcetera are doing so at the expense of the utility of the training. If someone judges their performance solely based on their status relative to others it reflects a distinct lack of self esteem. The idea of the style training is to develop self-esteem to increase capacities in many, many different modalities. A person who compromises training in order to beat others harms their self esteem. People know inherently when they are doing something wrong and there is a price to pay when they go against what they know is right.
 
Spotting Clock Whores: I imagine it is the same a proctoring an exam – The person who is constantly looking for the instructor is suspect. Another suspect behavior is always partnering with the same person when they score their workout. If some only does a full range of motion when the instructor is looking, then they are suspect. These behaviors are not hard and fast. On more than one occasion I have been called out by my instructors, rightly so, for ROM violation because I was exhausted. (The call outs are done with much joy and aplomb.)We all have issues when we get tired, it is part of the training. I have asked Tamer on more than several occasions what rep he was on because I had no idea where I was. The real difference is the consistent corner cutting. It takes time to become apparent, but when it is, it is like the giant elephant in the room no one acknowledges.