Separate 'pop-up' pictures, etc. (5)
I believe the answer is:
apart
'separate' is the definition.
(similar in meaning)
'pop-up pictures etc' is the wordplay.
I cannot quite see how this works, but
'pop' could be 'pa' (both can mean father) and 'pa' is located in the answer.
'pictures' could be 'art' and 'art' is found within the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for apart that I've seen before include "Independently" , "(Break) into pieces" , "cut off from others" , "in isolation" , "No longer living together" .)