Former spouse given enough warning (7)
I believe the answer is:
example
'warning' is the definition.
(example is a kind of warning)
'former spouse given enough' is the wordplay.
'former spouse' becomes 'ex'.
'given' means one lot of letters go next to another.
'enough' becomes 'ample' (I've seen this before).
'ex'+'ample'='EXAMPLE'
(Other definitions for example that I've seen before include "Thing illustrating a general rule" , "Illustration or model" , "Prototype" , "Specimen, sample" , "Punishment" .)