A stable one? (3)

I believe the answer is:

lad

I'm a little stuck... Click here to teach me more about this clue!

But I can't explain it at all! Could you help me understand?

(Other definitions for lad that I've seen before include "Boy, familiar" , "Youngster" , "A young chap into ballads" , "(Housman's Shropshire) boy" , "Young fellow" .)

Want a hint initially instead of a full solution? Install my app