Style estimated nicest (6)
I believe the answer is:
cutest
'nicest' is the definition.
Both the definition and answer are superlative adjectives. Maybe they are linked in a way I don't understand?
'style estimated' is the wordplay.
'style' becomes 'cut' (cut is a kind of style).
'estimated' becomes 'est' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'cut'+'est'='CUTEST'
Can you help me to learn more?
(Other definitions for cutest that I've seen before include "Most sweet and endearing" , "Most appealing" , "Smartest" , "Most clever" , "Most attractive in an endearing way" .)