Wit posed with anger (6)
I believe the answer is:
satire
'wit' is the definition.
(satire is a kind of wit)
'posed with anger' is the wordplay.
'posed' becomes 'sat' ('sit' can be a synonym of 'pose').
'with' means one lot of letters go next to another.
'anger' becomes 'ire' (synonyms).
'sat'+'ire'='SATIRE'
(Other definitions for satire that I've seen before include "Parody, spoof" , "sort of ironic humour" , "Sarcastic humour" , "Jonathan Swift's forte?" , "Irony or sarcasm in speech or writing" .)