Wruncle
The member of your family most likely to engage younger family members in inappropriate games, touching, or molestation. Also can be verbed. Origins lie in the combining of wrong and uncle.
-Johnny's walking funny today from what must have been a fierce-some wruncling last night.
-You don't want to leave the little ones alone around Wruncle Paul.
-You don't want to leave the little ones alone around Wruncle Paul.