Papa rates practical jokes (6)
I believe the answer is:
pranks
'practical jokes' is the definition.
(I've seen this in another clue)
'papa rates' is the wordplay.
'papa' becomes 'P' (NATO / phonetic alphabet).
'rates' becomes 'ranks' ('rank' can be a synonym of 'rate').
'p'+'ranks'='PRANKS'
(Other definitions for pranks that I've seen before include "Practical jokes, pieces of mischief" , "Tricky things to play" , "Tricks" , "Jokes, capers" .)