Definitions include: A circumcised male or circumcised penis. Well-known especially in Britain when boys compared their penises, and circumcision status, in school or college changing rooms. The uncircumcised are called cavaliers. The term refers humorously to the opposing sides in the English Civil War (1642-1651). In that war the Parliamentarians wore steel helmets and were nicknamed Roundheads. The Cavaliers were Royalists who had long flowing hair. The exposed glans penis of a circumcised male has some resemblance to such a helmet.
Definitions include: A male who thinks they are much cooler than they really are and generally has a Calvin pissing on something sticker, no fear gear or even better fear this on the back of their vehicle - normally a Mustang, Camaro, Firebird, etc.