Zoot suit vs. Gangster suit

Although it is now common for people looking for gangster or 1920's outfits to call them zoot suits this is erroneous.

A zoot suit is characterized by a long jacket with wide lapels and padded shoulders, high waisted wide legged pants that end in narrow cuffs.  Very often they were made in loud colors.
Zoot suits came much much later than the classic gangster suit and the 1920's. Primarily worn by Latino youths during the second
world war, they were also worn by other 'minority' groups at the time including African Americans, and Italians.  Similar to the trend of oversized pants and shirts worn by some of todays youth to make them stand out from the rest of society.
During the WWII they were considered by those in power to be a waste of needed materials. Which led to heightened tensions between the military men stationed in southern California and the Latino youths, that tension turned into the Zoot Suit Riots of 1943.

Gangsters, and other men in the 1920's (which was all of them at some point in the week) wore suits.  Typically double breasted with standard size darted lapels. Pinstripes were common and ties were on the skinnier side.
Big difference  between the two styles and an even bigger difference in the statement made.