Unsuccessful football manager took charge after international (6)
I believe the answer is:
failed
'unsuccessful' is the definition.
(similar in meaning)
'football manager took charge after international' is the wordplay.
'football manager' becomes 'FA' (the Football Association manages English football).
'took charge' becomes 'led' (lead can mean to take charge).
'after' says to put letters next to each other.
'international' becomes 'i' (abbreviation eg in IMF).
'led' after 'i' is 'iled'.
'fa'+'iled'='FAILED'
(Other definitions for failed that I've seen before include "Bankrupt" , "Didn't make it - not well" , "Did not succeed, perhaps at exam" , "Was unsuccessful, did not pass exam" , "Didn't succeed" .)