Character revealed by stethoscope (5)
I believe the answer is:
ethos
'character' is the definition.
(thesaurus)
'revealed by stethoscope' is the wordplay.
'revealed by' says the answer is hidden in the clue.
'ETHOS' can be found hidden inside 'stethoscope'.
(Other definitions for ethos that I've seen before include "Moral significance" , "Characteristic spirit of a community - for those" , "Distinctive attitude (of culture, person etc)" , "Characteristic attitude" , "Characteristic standards of those" .)