youngster

   This term is normally used to a boy, though it could theoretically apply to a girl. In the eighteenth century the word was specifically used of boys and junior seamen on board ship. It was sometimes extended to junior officers, in the army as well as the navy. Earlier still, in the sixteenth and seventeenth centuries, ‘youngster’ carried a suggestion of liveliness and briskness, though coupled with immaturity.

   Normal modern usage of the vocative is shown in The Island, by Peter Benchley: ‘What did you say your name was, youngster?’ ‘Justin.’ ‘Well, Justin, why don’t you carry this for me?’ In Tender is the Night, by F.Scott Fitzgerald, Rosemary says to Dick: ‘I must go, youngster.’ This is a joke, referring back to an earlier discussion between them where Dick has pointed out that he is a middle-aged man while she is still almost a child.