1: the ability in which to resemble a retarded
person in behavior by being limited in
intellectual or emotional development---often taken to be offensive
2: the development or academic progress of retarding others
3: the act or instance the extent to which
something may be affected with retardedness
You're so naturally retardable, playing the part of a mentally challenged
person comes easily to you.
I'm sorry I keep screwing things up, I'm feeling quite retardable
today.
That was very retardable of you to remember to flush the
toilet, but forget to wipe.