c.1200, from Old French peril "danger, risk" (10c.), from Latin periculum "an attempt, trial, experiment; risk, danger," with instrumentive suffix -culum and first element from PIE *peri-tlo-, suffixed form of root *per- (3) "to lead, pass over" (cognates: Latin experiri "to try;" Greek peria "trial, attempt, experience," empeiros "experienced;" Old Irish aire "vigilance;" Gothic ferja "watcher;" Old English fær "danger, calamity"); related to *per- (1) "forward, through" (see per).