Nerd (noun) = A foolish, inept, or unattractive person. A person who is single-minded or accomplished in scientific or technical pursuits but is felt to be socially inept (nova gíria para "square", dos anos 50-70)

Geek (noun) = young people who spend their youth studying at the expense of their social life (ou seja, um CDF)

Scenester (noun) = (Youthspeak) Someone intent on "making the scene," a really cool groupie always at the right band concerts, hanging with the right nest of other cool groupies. Scenesters are identified by their drab clothes, smoking, drug use (or talk of drug use), use of cool words from in(tellectual) magazines, which they don't know the meaning of, and lack of attention to the music at the concerts they attend. An offensive hair-do is a must, if not with spikes and bizarre colors, at least with highlights. The antonym is "geek."
Usage: This word refers to groupies or "band aids," young people who follow bands from concert to concert and who become disdainful in their knowledge of the lore of contemporary rock bands. Scenesters often end up working for geeks in later life. Ouch!

Dud = One that is disappointingly ineffective or unsuccessful.

Sucker (noun) = One who is easily deceived; a dupe. One that is indiscriminately attracted to something specified: “The nation's capital is a sucker for a symbolic gesture”