Tough being cute? (6)
I believe the answer is:
severe
'tough' is the definition.
(thesaurus)
'being cute?' is the wordplay.
I cannot quite understand how this works, but
'being' could be 'eve' (Eve is an example) and 'eve' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
(Other definitions for severe that I've seen before include "Strait-laced" , "Austere, spartan" , "Sharp" , "Extremely difficult to endure" , "Ascetic - demanding - bitter" .)