Any item of clothing your parents are forcing you to wear but you know looks outdated & 'pants'
Father 'Son, put your lederhosen on'
adj. Pertaining to an item of clothing that is very naff, and provokes the response, "No, Dad!" The implication is that only a dad would wear such a heinous crime against fashion, and that by doing so he would embarrass his children.
"Dude, what were you thinking putting that on to take your girlfriend out. That's a nodad shirt."