1
general::
very frightening
terrifying
extremely frightening:
• a terrifying thought • The experience was absolutely terrifying. • She spoke of the terrifying ordeal (= a very bad experience ) when three armed men burst into her house.
hair-raising
very frightening and involving danger, in a way that is exciting:
• hair-raising stories • a hair-raising motorcycle ride through the streets of Havana
spine-chilling
very frightening – used about films, stories etc that involve frightening or cruel events:
• a spine-chilling novel by Stephen King
blood-curdling
especially literary [ only before noun ] very frightening – used especially about sounds:
• a blood-curdling scream • a blood-curdling growl
Longman-Thesaurus