A cat in charge on a very small level (6)
I believe the answer is:
atomic
'a very small level' is the definition.
Both the definition and answer are adjectives. Perhaps there's an association between them I don't understand?
'a cat in charge on' is the wordplay.
'cat' becomes 'tom' (a tom is a male cat).
'in charge' becomes 'ic' (abbreviation for 'in charge').
'on' says to put letters next to each other.
'a'+'tom'+'ic'='ATOMIC'
Can you help me to learn more?
(Other definitions for atomic that I've seen before include "Sort of energy or number" , "Like nuclear energy" , "nuclear issues?" , "Relating to tiny particles" , "Employing nuclear energy" .)