What does 띨띨 Mean?
I watched this episode of family Outings, a korean reality-type show, and in it i heard one of the lady's call this guy "띨띨 멍청해" Now I looked it up and meongcheonghae means stupid.. and it said ddil ddil means asshole, but is that true? I don't think it is because i don't think they would use a curse word on the show.. but is it?

Question

Answer

It's slang. 

Noun : 띨띨이(moron)
Adjective verb : 띨띨하다(see reira's answer) 

쟤 띨띨이야. S/he is such a moron. 
쟤 좀 띨띨해. S/he is kind of stupid. 

Also 어리버리하다 means the same thing. I think 띨띨하다 is a bit more offensive.

Answer

띨띨 means stupid and foolish and silly same.