Game is rigged — it indicates bias (6)
I believe the answer is:
ageism
'it indicates bias' is the definition.
The definition suggests a singular noun which matches the answer.
'game is rigged' is the wordplay.
'rigged' indicates an anagram.
'game'+'is'='gameis'
'gameis' with letters rearranged gives 'AGEISM'.
Can you help me to learn more?
(Other definitions for ageism that I've seen before include "Prejudice or bias against old people" , "Prejudice against senior citizens" , "Prejudice against older people" , "Prejudice on grounds of age" , "Non-PC attitude to senior citizens" .)