Disdain metric conversion: was judgmental (13)
I believe the answer is:
discriminated
'was judgmental' is the definition.
(to discriminate is to be judgmental or prejudiced)
'disdain metric conversion' is the wordplay.
'conversion' indicates an anagram.
'disdain'+'metric'='disdainmetric'
'disdainmetric' is an anagram of 'DISCRIMINATED'.
(Other definitions for discriminated that I've seen before include "biased" , "Distinguished - treated unfairly" , "Dancer is timid (anag) -- treated differently" .)