flasher

• POS: Noun
• HYPHEN: flash=er

CIDE DICTIONARY

flasher, n. 

•  One who, or that which, flashes.  [1913 Webster]
•  A man of more appearance of wit than reality.  [1913 Webster]
•  A large sparoid fish of the Atlantic coast and all tropical seas (Lobotes Surinamensis).  [1913 Webster]
•  An exhibitionist{1}, especially a male, who briefly exposes his private parts in a public place.  [PJC]

OXFORD DICTIONARY

flasher, n.
1 Brit. sl. a man who indecently exposes himself.
2 a an automatic device for switching lights rapidly on and off. b a sign or signal using this.
3 a person or thing that flashes.