To make less harsh, less rude, less offensive, or less violent, or to render of an opposite quality.
To make less glaring; to tone down; as, to soften the coloring of a picture.
To make less harsh or grating, or of a quality the opposite; as, to soften the voice.
To become soft or softened, or less rude, harsh, severe, or obdurate.
make less severe or harsh; "He moderated his tone when the students burst out in tears"