Foul

The chess player committed a foul by moving his knight diagonally.

The neglected house had foul walls covered in grime and mold.

The foul stench emanating from the garbage bin was unbearable.

The foul air inside the abandoned building was thick with dust and decay.

The foul smell of rotten eggs filled the kitchen.

The foul smoke from the burning forest obscured the sun and created a gloomy atmosphere.