The action of cheating where you are the individual with whom a person in a relationship is cheating.
or
The action of cheating in which you are not in a relationship, but the person with whom you're fratternizing with, is.
AKA = the other man or the other woman
Monika Lewinsky addered with Bill Clinton.
Administrators n shit...
an adder just joined the game
the adders joined the game
"I'll never lend Steve my jazz-mags again. When he gave them back all the best pages were covered in bladder adder snot. The twat."