Stop disheartened and study range (6)
I believe the answer is:
spread
'range' is the definition.
(thesaurus)
'stop disheartened and study' is the wordplay.
'disheartened' suggests removing the centre.
'and' says to put letters next to each other.
'study' becomes 'read' ('read' can be a synonym of 'study').
'stop' with its middle removed is 'sp'.
'sp'+'read'='SPREAD'
(Other definitions for spread that I've seen before include "Stretch out; big meal" , "Broadcast" , "Stretch out; large meal" , "Sort of betting" , "Special display" .)