Refers to a thin mist or smoke.
El esfumin que salía de la chimenea era un claro indicador de que alguien estaba cocinando en la casa.
The smoke coming from the chimney was a clear indicator that someone was cooking in the house.
El esfumin de la fogata iluminaba tenuemente el oscuro bosque durante la noche.
The smoke from the bonfire faintly illuminated the dark forest during the night.