Spot Greek character nursing temperature (6)
I believe the answer is:
stigma
'spot' is the definition.
(thesaurus)
'greek character nursing temperature' is the wordplay.
'greek character' becomes 'sigma' (letter from the Greek alphabet).
'nursing' is an insertion indicator.
'temperature' becomes 't' (abbreviation).
'sigma' enclosing 't' is 'STIGMA'.
(Other definitions for stigma that I've seen before include "Symbol of disgrace or infamy" , "Badge of shame" , "Disgraceful mark" , "part of plant" , "Mark of shame or social disgrace" .)