[re.lapse] n [ME, fr. ML relapsus, fr. L relabi to slide back, fr. re- + labi to slide--more at sleep] (15c) 1: the act or an instance of backsliding, worsening, or subsiding
2: a recurrence of symptoms of a disease after a period of improvement
[2]re.lapse vi re.lapsed ; re.laps.ing (1568) 1: to slip or fall back into a former worse state
2: sink, subside "~ into deep thought" -- re.laps.er n