Definition of "younker"

“Jim,” says he, “I reckon we’re fouled, you and me, and we’ll have to sign articles. I’d have had you but for that there lurch, but I don’t have no luck, not I; and I reckon I’ll have to strike, which comes hard, you see, for a master mariner to a ship’s younker like you, Jim.”

1883, Robert Louis Stevenson, Treasure Island

So foorth they went, and both together giusted; But that same younker soone was overthrowne

1596, Edmund Spenser, “Book IV, Canto I”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie

Trimmed like a younker prancing to his love!

c. 1591–1592 (date written), William Shakespeare, “The Third Part of Henry the Sixt, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, [Act II, scene i]