1. (

• devil ,
• fiend ,
• demon ,
• daemon ,
• daimon

) an evil supernatural being ;

2. (

• monster ,
• fiend ,
• devil ,
• demon ,
• ogre ,

) a cruel wicked and inhuman person ;

3. (

• demon ,

) someone extremely diligent or skillful; "he worked like a demon to finish the job on time"; "she's a demon at math" ;