Conscious of disheartened advocate having internal conflict (5)
I believe the answer is:
aware
'conscious of' is the definition.
(being conscious means being aware of something)
'disheartened advocate having internal conflict' is the wordplay.
'disheartened' says to hollow out the word (remove centre letters) (the middle or heart is removed).
'having internal' means one lot of letters goes inside another.
'conflict' becomes 'war' (war is a kind of conflict).
'advocate' with its middle removed is 'ae'.
'ae' going around 'war' is 'AWARE'.
(Other definitions for aware that I've seen before include "fly" , "Knowing (of something)" , "Alert, conscious of" , "Bearing in mind" , "Acquainted with or conscious of" .)