Found in Inverness, a youth's written composition (5)
I believe the answer is:
essay
'written composition' is the definition.
(I've seen this in another clue)
'found in inverness a youth's' is the wordplay.
'found in' says the answer is hidden in the clue.
'ESSAY' can be found hidden inside 'inverness a youths'.
(Other definitions for essay that I've seen before include "Endeavour" , "Attempt - piece of writing" , "Attempt, try" , "Test" , "Analytic or interpretive literary composition (5_" .)