Definition from Wiktionary, the free dictionary
Proper noun 
Guido (plural Guidos)
- A male given name of Italian origin. English equivalent: Guy
- (US, slang, pejorative) a young, lower class or working class Italian-American or Italian-Canadian male from an urban environment.
- (US, slang, pejorative) A clothing style associated with the stereotype.
Usage notes 
- Carries the connotation of a person who is humorously uncultured and has a thuggish and overtly macho attitude and an unyielding pride in his Italian ancestry. Common in Northeast areas such as Brooklyn, the Bronx, Queens, Staten Island, New Jersey, South Philadelphia, Baltimore, Boston, Rhode Island and Southwest Connecticut.
- The fashion style includes gold or platinum chains, diamond stud earrings, plain T-shirts or muscle shirts, tracksuits, pompadours, slicked-back hair, or blowout hairstyles
Alternative forms 
- (pejorative sense (of a person)): guido
Coordinate terms 
See also 
Of Germanic origin.
Proper noun