Is it ensure, insure, or assure?
"frenzy or rapture supposed to take hold of a man upon gazing on a nymph," 1775, coined by Richard Chandler, in "Travels in Greece," from nymph, on model of epilepsy, with second element from stem of Greek lambanein "to take." Especially "an ecstasy or frenzy caused by desire for the unattainable." Ancient Greek had nympholeptos "caught by nymphs." Related: Nympholept; nympholeptic.