Gladstone's youth (3)
I believe the answer is:
lad
'youth' is the definition.
(lad means a young man)
'gladstone's' is the wordplay.
'LAD' is hidden within the letters.
However, I am unsure how the hidden word is indicated.
Can you help me to learn more?
(Other definitions for lad that I've seen before include "Stable worker" , "Youngster" , "Boy or youth" , "Chap, fellow" , "(Housman's Shropshire) boy" .)