Dad’s come up, popping in to contradict and censure (10)
I believe the answer is:
disapprove
'censure' is the definition.
(I've seen this before)
'dad's come up popping in' is the wordplay.
'dad' becomes 'pa' (both can mean one's father).
'come up' says the letters should be written in reverse.
'popping' becomes 'disprove' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'pa' back-to-front is 'ap'.
'ap' placed within 'disprove' is 'DISAPPROVE'.
'to contradict and' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for disapprove that I've seen before include "Hold an unfavourable opinion (of something)" , "Censure" , "Not like" , "Not be happy with" , "Reject" .)