A person that a male or female who is single seeks out for a one night stand to break their current "drought". A drought breaker is usually an individual whom you have no feelings for, but because of their affection for you or lack of self-esteem they fall back into the habit of sleeping with you on the notion that they might once again have a chance to date you. A drought breaker also leads to a boost in self-esteem for the party initiating the hookup.
Tim: "Hey bro, haven't had sex in three weeks, gotta hit up Karen to break my drought."
Larry: "Yeah man, she does make a great drought breaker."