devil

Concise Oxford English Dictionary © 2008 Oxford University Press:
devil/ˈdevl/

▶noun

• 1 (usu. the Devil) (in Christian and Jewish belief) the supreme spirit of evil; Satan.

  ■ an evil spirit; a demon.

• 2 a very wicked or cruel person.

  ■ a mischievously clever or self-willed person.

• 3 (the devil) fighting spirit; wildness: he was born with the devil in him.

• 4 (the devil) a thing that is very difficult or awkward to do or deal with.

• 5 informal a person with specified characteristics: you lucky devil.

• 6 (the devil) expressing surprise or annoyance in various questions or exclamations.

• 7 an instrument or machine used for tearing or other destructive work.

• 8 informal, dated a junior assistant of a barrister or other professional. See also printer's devil.

▶verb (devils, devilling, devilled; US devils, deviling, deviled)

• 1 informal, dated act as a junior assistant for a barrister or other professional.

• 2 N. Amer. harass or worry.

– phrases
be a devil! Brit. informal said when encouraging someone to do something that they are hesitating to do.
between the devil and the deep blue sea caught in a dilemma.
devil-may-care cheerful and reckless.
the devil's dozen thirteen.
the devil's in the detail the details of a matter are its most problematic aspect.
the devil to pay serious trouble to be dealt with.
like the devil with great speed or energy.
play the devil with have a damaging or disruptive effect on.
speak (or talk) of the devil said when a person appears just after being mentioned. [from the superstition that the devil will appear if his name is spoken.]

– origin OE dēofol, via late L. from Gk diabolos ‘accuser, slanderer’ (used in the Septuagint to translate Heb. śāṭān ‘Satan’), from diaballein ‘to slander’.