Feeble leaders from England and France attending festivity (6)
I believe the answer is:
effete
'feeble' is the definition.
(I've seen this before)
'leaders from england and france attending festivity' is the wordplay.
'leaders from' says to take the initial letters.
'and' is a charade indicator (letters next to each other).
'france' becomes 'f'.
'attending' says to put letters next to each other.
'festivity' becomes 'fete' (fete is a kind of festivity).
The initial letter of 'england' is 'e'.
'e'+'f'+'fete'='EFFETE'
(Other definitions for effete that I've seen before include "Feeble, having lost vitality" , "Enfeebled" , "Ineffective, decadent" , "Lacking in power" , "Over-refined, pretentious" .)