1.To slip or slide back, in a literal sense; to turn back. (Obs.)
2.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. "That task performed, (preachers) relapse into themselves."
3.(Theol.) To fall from Christian faith into paganism, heresy, or unbelief; to backslide. "They enter into the justified state, and so continue all along, unless they relapse."
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