Second young creature — is that clear? (3,2)
I believe the answer is:
mop up
'second young creature is that clear?' is the definition.
The definition and answer can be both acts as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'second young' is the wordplay.
I cannot quite understand how this works, but
'second' could be 'mo' (both are short periods of time) and 'mo' is found within the answer.
'young' could be 'pup' (pup is a kind of young) and 'pup' is located in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for mop up that I've seen before include "take care of" , "Deal with spillage or defeated enemy" , "Finish a task, clear away remnants" , "Finish off a task, clean away remnants" , "Kill (enemy stragglers)" .)