To erase (as anything impressed or inscribed upon a surface); to render illegible or indiscernible.
Do not efface what I've written on the chalkboard.
To cause to disappear as if by rubbing out or striking out.
Some people like to efface their own memories with alcohol.
To make oneself inobtrusive as if due to modesty or diffidence.
Many people seem shy, but they really just efface for meekness.
Of the cervix during pregnancy, to thin and stretch in preparation for labor.
Some females efface 75% by the 39th week of pregnancy.