No friendly society would show this (6)
I believe the answer is:
enmity
'no friendly society would show this' is the definition.
The definition suggests a singular noun which matches the answer.
This is all the clue.
Can you help me to learn more?
(Other definitions for enmity that I've seen before include "Hate; aversion" , "Personal hostility" , "Hostility, bad feeling towards" , "Hostility between opposing people or countries" , "Hostility, ill-will" .)