Applauds sweetheart, accepting over large failure (8)
I believe the answer is:
collapse
'failure' is the definition.
(thesaurus)
'applauds sweetheart accepting over large' is the wordplay.
'applauds' becomes 'claps' ('clap' can be a synonym of 'applaud').
'sweetheart' becomes 'e' (the heart/centre of 'sweet').
'accepting' is an insertion indicator.
'over' becomes 'o' (cricket abbreviation**).
'large' becomes 'l'.
'claps'+'e'='clapse'
'o'+'l'='ol'
'clapse' placed around 'ol' is 'COLLAPSE'.
(Other definitions for collapse that I've seen before include "Faint and fall" , "Fall down suddenly like escallop" , "Give way, fail suddenly" , "Go to ruin" , "Break down - fall" .)