Member overcome by English youth leader’s lament (5)
I believe the answer is:
elegy
'lament' is the definition.
('elegy' can be a synonym of 'lament')
'member overcome by english youth leader's' is the wordplay.
'member' becomes 'leg' (I've seen this before).
'overcome by' is an insertion indicator.
'english' becomes 'e' (abbreviation).
'youth leader' becomes 'y' (I've seen this in other clues).
'e'+'y'='ey'
'leg' inserted inside 'ey' is 'ELEGY'.
(Other definitions for elegy that I've seen before include "Poem as Gray's in churchyard" , "Sad work" , "Poem for the departed" , "Sad words" , "Mournful poem, lament" .)