stain, spot
Há apenas uma mancha marrom agora onde aquele pássaro estava.
There's just a brown spot now where that bird was.
— It's Such a Beautiful Day (2012)
A mancha marrom nas costas, parece que deitou num monte de merda.
The brown stain on his back looks like he lay down in a pile of shit.
— Mommy (2014)
Tá estragando a porra da mancha criminal.
You're fucking up the damn criminal record.
— Tropa de Elite (2007)