MOD short for Modern, was a Clique created in England (1960s) where the youth, in an attempt to be avant-guard, created a scene of scooter riding, snappy dressing, listeners of soul music or modern jazz.  This clique spread across the world and is still seen today.
The ROCKERS were the Mods antithesis and the two often brawled causing media coverage and notoriety.

MUSTS, TO BE MOD: Vespa or Lambretta scooter, tailored clothing, dancing all night to soul music.
As Pop Art was in vogue, Mod clothing had bold colors and shapes. - Think of the dance scene in Austin Powers.  Mod was an offshoot of Beatnik and the pseudo-intellect, self-centered aspect was still there, as Mod Youths tried to find their place in existence (existentialism).