nerd

Somebody who acts in a way that makes no sense to you. In modern U.S.-originated global culture, the term is mostly used by jocks to refer to brainiacs, but in mid-Twentieth century Britain, a nerd was more usually someone who acted foolishly or recklessly, without considering the consequences, or was simply clumsy. Consider: A student sits in the library studying hard for an important exam tommorrow. Her fun-loving soon-to-be burger flipper classmate lounges about on the grass outside soaking up some rays. Each looks through the window at the other and declares "What a nerd!" Nerd can be used as an affectionate put-down among friends, usually indicating foolishness, or as a calculated insult, where it's meaning is somewhere between loser and geek.