Gladstone's son (3)
I believe the answer is:
lad
'son' is the definition.
(lad can mean a boy or son)
'gladstone's' is the wordplay.
'LAD' is hidden in amongst the letters.
But, I'm unsure how this is indicated.
Can you help me to learn more?
(Other definitions for lad that I've seen before include "Stable employee" , "Son" , "Boy, familiar" , "(Housman's Shropshire) boy" , "Boy or youth" .)