look up any word, like doxx:
 
1.
A bet in which nothing is wagered. The winner recieves nothing but respect.
Guy A: There's no way you're winning this one.
Guy B: Wanna bet?
Guy A: Yeah! It's on!
Guy B: Eat shit because i just won.
Guy A: Well we didn't bet shit so I guess it was a gentleman's bet.
by Jay Danger July 10, 2008
 
2.
A wager on principle rather than for significant amounts of money.
A typical Gentleman's Bet will be for no money or a nominal sum (e.g., $1) with the "prize" of being correct going to the winner. Think of Trading Places and the bet the Duke brothers made.
by thesellman April 16, 2014
 
3.
A common bet done in Middle school or High school when idiot men do a little of manly toughness when getting the affections of really pretty girls. For example, a commmon gentlemen's bet sounds like:

Hey i bet i can get her number before you can.
other guy: You're on!Lets start this gentleman's bet
by MikeTao September 09, 2007