"What an idiot" = Que idiota
"he/she is toast" = ele/ela acabou (he/she is finished/done)
"he/she is hot" = gostoso/gostosa

other random phrases:

i'm hungry = eu estou com fome
i'm thirsty = eu estou com sede
i'm tired = eu estou cansado
lose = perder
win = ganhar
immunity = imunidade
fire = fogo
water = agua

If anyone can think of anymore, I can help out.
I could be wrong on the spelling.. I was never really taught how to spell/write in Portuguese. I only know it from living in Brazil for 4 years. =P