Make fun of practice examination (4)
I believe the answer is:
mock
'make fun' is the definition.
(thesaurus)
'practice examination' is the wordplay.
'practice' becomes 'mo' (abbreviation for modus operandi).
'examination' becomes 'ck' (I can't justify this - if you can you should give a lot more credence to this answer).
'mo'+'ck'='MOCK'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for mock that I've seen before include "Unreal; ridicule" , "Imitation; tease scornfully" , "Deride - false" , "Treat with contempt -- imitation" , "Scoff at" .)