v. i. - To slip or slide back, in a literal sense; to turn back.
v. i. - To slide or turn back into a former state or practice; to fall back from some condition attained; -- generally in a bad sense, as from a state of convalescence or amended condition; as, to relapse into a stupor, into vice, or into barbarism; -- sometimes in a good sense; as, to relapse into slumber after being disturbed.
v. i. - To fall from Christian faith into paganism, heresy, or unbelief; to backslide.
v. - A sliding or falling back, especially into a former bad state, either of body or morals; backsliding; the state of having fallen back.
v. - One who has relapsed, or fallen back, into error; a backslider; specifically, one who, after recanting error, returns to it again.