Those changed in spirit (5)
I believe the answer is:
ethos
'spirit' is the definition.
(I've seen this before)
'those changed' is the wordplay.
'changed' indicates an anagram.
'those' is an anagram of 'ETHOS'.
'in' acts as a link.
(Other definitions for ethos that I've seen before include "Characteristic culture of a culture or time" , "Distinctive principles of an era, group, etc" , "Distinctive spirit - character" , "Characteristic spirit, of a culture say" , "Group's distinctive character" .)