This poser is after snappy conversation (9,6)
I believe the answer is:
crossword puzzle
'this' is the definition.
(this is a crossword puzzle!)
'poser is after snappy conversation' is the wordplay.
'poser' becomes 'puzzle' (poser can mean a puzzle or question).
'is after' means one lot of letters go next to another.
'snappy' becomes 'cross' (both can mean bad-tempered).
'conversation' becomes 'word' (as in having a word with someone).
'cross'+'word'='crossword'
'puzzle' put after 'crossword' is 'CROSSWORD PUZZLE'.
(Another definition for crossword puzzle that I've seen is " This".)