blacken

verbs

make or become black
"The smoke blackened the ceiling"; "The ceiling blackened"
black, blacken, melanise, melanize, nigrify
antonym
whiten
burn slightly and superficially so as to affect color
"The cook blackened the chicken breast"; "The fire charred the ceiling above the mantelpiece"; "the flames scorched the ceiling"
blacken, char, scorch, sear