So the shiftiness is due to people's general attitudes, etc. (5)
I believe the answer is:
ethos
'so' is the definition.
Although both the answer and definition are singular nouns, I can't understand how they can define each other.
'the shiftiness is due to people's general attitudes etc' is the wordplay.
I cannot really see how this works, but
an anagram of 'the' is 'eth' which is present in the answer.
'people's' could be 'os' (O is an example) and 'os' is located in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for ethos that I've seen before include "Culture, way of life" , "Distinctive spirit - character" , "Characteristic culture of a culture or time" , "Distinctive group attitudes" , "Distinctive spirit of an institution" .)