Hello. The true translation would not be "vous êtes perdant' but "vous êtes UN perdant". Anyway, this expression does not really exist in french because it's an english culture root one. Most in france we use the wor "looser" to say looser :D (ex : tu es un looser)

you are a loser i french is "vous êtes perdant" english pronounciation is" u r a lu_sir" hope that helps