Definition of imperilous in English:

imperilous

Pronunciation /ɪmˈpɛrɪləs/ /ɪmˈpɛr(ə)ləs/

adjective

rare
  • Perilous; dangerous (to someone or something).

Origin

Mid 17th century; earliest use found in John Bond (1612–1676), college head. Alteration of perilous, after imperil.