Boy upset about some troubled maiden (7)
I believe the answer is:
damosel
'maiden' is the definition.
(I know that damosel is a type of maiden)
'boy upset about some troubled' is the wordplay.
'boy' becomes 'lad' (informal term for boy).
'upset' says the letters should be written in reverse.
'about' indicates putting letters inside.
'troubled' is an anagram indicator.
'lad' reversed gives 'dal'.
'some' with letters rearranged gives 'mose'.
'dal' going around 'mose' is 'DAMOSEL'.
(Other definitions for damosel that I've seen before include "Old term for young woman" , "Maiden, in poetry" .)