frightening
Concise Oxford English Dictionary © 2008 Oxford University Press:
frighten/ˈfrʌɪtn/
▶verb cause to be afraid.
■ (frighten someone off) drive someone away by frightening them.
– derivatives
frightened adjective,
frightening adjective,
frighteningly adverb.
frightened adjective,
frightening adjective,
frighteningly adverb.
'frightening' also found in these Oxford entries:
blood-curdling
- eerie
- fearsome
- frighten
- frightener
- gorgon
- hair-raising
- monster
- monstrous
- nightmare
- pluck
- scare
- scaremonger
- scary
- spine-tingling

