c.1200, from Old French peril "danger, risk" (10c.), from Latin periculum "an attempt, trial, experiment; risk, danger," with instrumentive suffix -culum and element also found in experiri "to try," cognate with Greek peria "trial, attempt, experience," empeiros "experienced," Old Irish aire "vigilance," Gothic ferja "watcher," Old English fær "danger, fear" (see fear (n.)).