Former partner given sufficient warning (7)
I believe the answer is:
example
'warning' is the definition.
(as in making an example of someone)
'former partner given sufficient' is the wordplay.
'former partner' becomes 'ex' (an ex-partner).
'given' is a charade indicator (letters next to each other).
'sufficient' becomes 'ample' (both can mean enough).
'ex'+'ample'='EXAMPLE'
(Other definitions for example that I've seen before include "Specimen, sample" , "Model - instance" , "Typical specimen" , "Illustrative case" , "Representative object" .)