demon
noun /ˈdiːmən/
  /ˈdiːmən/
Idioms - an evil spirit
- The people believed the girl was possessed by demons.
 
Extra Examples- demons torturing the sinners in Hell
 - an ancient ritual to exorcise demons
 - tales of travellers attacked by evil demons
 
Oxford Collocations Dictionaryadjective- evil
 - inner
 - personal
 - …
 
- be possessed by
 - cast out
 - exorcize
 - …
 
 - something that causes a person to worry and makes them unhappy
- the demons of jealousy
 - She's had to battle her personal demons throughout her adult life.
 - He is plagued by demons which go back to his traumatic childhood.
 
Oxford Collocations Dictionaryadjective- evil
 - inner
 - personal
 - …
 
- be possessed by
 - cast out
 - exorcize
 - …
 
 - (informal) a person who does something very well or with a lot of energy
- He skis like a demon.
 - He’s a demon: he gets up early, he works out, he goes home early, he studies, he works out again…
 
 
Word OriginMiddle English: from medieval Latin, from Latin daemon, from Greek daimōn ‘deity, genius’; in sense (1) also from Latin daemonium ‘lesser or evil spirit’, from Greek daemonion, diminutive of daimōn.
Idioms 
the demon drink 
- (British English, humorous) alcoholic drink