Simple Definition of maniac
: someone who is violent and mentally ill
: a person who behaves in a very wild way
: a person who is extremely enthusiastic about something
Examples of maniac in a sentence
He's a complete maniac when he's playing football.
<they should permanently put away the maniac who is responsible for these kidnappings>
Origin and Etymology of maniac
Late Latin maniacus maniacal, from Greek maniakos, from mania
First Known Use: circa 1763
MANIAC Defined for Kids
Definition of maniac for Students
1 : a person who is or behaves as if insane
2 : a person who is extremely enthusiastic about something
Seen and Heard
What made you want to look up maniac? Please tell us where you read or heard it (including the quote, if possible).