Sep 24, 2025 ghastly ˈgast-lē 2 syllables uncommon ‹ adjective.terrifyingly horrible to the senses: frightening a ghastly crime… such a life seems ghastly in its emptiness and sterility. adjective.intensely unpleasant, disagreeable, or objectionable a ghastly mistake adjective.resembling a ghost › Origin Middle English gastly, from gasten to terrify.