demon

UK: /ˈdiːmən/ US: /ˈdimən/ ,(dē′mən)

WordReference Random House Learner's Dictionary of American English © 2026

de•mon /ˈdimən/   n. [countable]

1. an evil spirit; fiend:
   a ceremony to exorcise demons from the haunted house.
2. a wicked or cruel person.
3. one with great energy:
   a demon for work.

de•mon•ic /dɪˈmɑnɪk/  adj. 

WordReference Random House Unabridged Dictionary of American English © 2026

de•mon  (dē′mən), n. 

1. an evil spirit;
   devil or fiend.
2. an evil passion or influence.
3. a person considered extremely wicked, evil, or cruel.
4. a person with great energy, drive, etc.:
   He's a demon for work.
5. a person, esp. a child, who is very mischievous:
   His younger son is a real little demon.
6. Mythology daemon.
7. British Terms [Australian Slang.] a policeman, esp. a detective.

adj. 

8. of, pertaining to, characteristic of, or noting a demon.
9. possessed or controlled by a demon.

• Latin; see daemon
• Greek daimónion, thing of divine nature (in Jewish and Christian writers, evil spirit), neuter of daimónios, derivative of daímōn; (def. 6)
• Latin daemonium
• Middle English 1350–1400

demon-, 

1. var. of demono- before a vowel:
   demonism.

Collins Concise English Dictionary © HarperCollins Publishers::

demon / ˈdiːmən/ noun

1. an evil spirit or devil
2. a person, habit, obsession, etc, thought of as evil, cruel, or persistently tormenting
3. Also called: daemon, daimon an attendant or ministering spirit; genius: the demon of inspiration
4. a person who is extremely skilful in, energetic at, or devoted to a given activity, esp a sport: a demon at cycling
5. (as modifier): a demon cyclist
6. a variant spelling of daemon1
7. a detective or police officer
8. a part of a computer program, such as a help facility, that can run in the background behind the current task or application, and which will only begin to work when certain conditions are met or when it is specifically invoked

Etymology: 15th Century: from Latin daemōn evil spirit, spirit, from Greek daimōn spirit, deity, fate; see daemon

WordReference Random House Unabridged Dictionary of American English © 2026

demono-, 

1. a combining form representing demon in compound words:
   demonology.

Also,[esp. before a vowel,] demon-.