nightmarish

1. Extremely alarming (synset 300196418)
   similar to: alarming - frightening because of an awareness of danger
   same as: bloodcurdling, hair-raising

Other Searches

• Rhyme: Dillfrog, RhymeZone
• Definition: Wiktionary, Dictionary.com, Wikipedia, Merriam-Webster, WordNet, Power Thesaurus
• Imagery: Google, Flickr, Bing