Admit mere wanton admitted nothing wanton (10)
I believe the answer is:
immoderate
'wanton' is the definition.
(thesaurus)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for immoderate that I've seen before include "Reckless" , "Excessive" , "over the top" , "Extravagant" .)