The spirit said to be within me (6)
I believe the answer is:
morale
'the spirit' is the definition.
(thesaurus)
'said to be within me' is the wordplay.
'said' becomes 'oral' (I've seen this before).
'to be within' indicates putting letters inside.
'oral' inserted within 'me' is 'MORALE'.
(Other definitions for morale that I've seen before include "Mood" , "The spirit of a group or individual" , "Group spirit and confidence" , "Spirits" , "Self-confidence" .)