johnny
noun
[ ˈdʒɒni ]
• used as a name for an unknown man, often suggesting that he is unimportant or insignificant.
• "the security johnny insists that you sign the visitors' book"
• a condom.
• a gown fastened at the back, worn by hospital patients.
Origin:
late 17th century (in johnny (sense 1 of the noun)): pet form of the given name John ; johnny (sense 2 of the noun) dates from the 1960s.