1. A person who is weak, cowardly, or easily frightened; someone lacking courage or bravery
Don't be such a wuss, just jump off the diving board!
Não seja tão medroso, só pule do trampolim!
2. A person who is overly sensitive or complains easily
He's being a wuss about the minor scrape on his knee.
Ele está sendo fresco por causa do arranhão pequeno no joelho.