Study the only comfort (7)
I believe the answer is:
console
'comfort' is the definition.
(I know that comfort can be written as console)
'study the only' is the wordplay.
'study' becomes 'con' (con can mean to study).
'the only' becomes 'sole' (I've seen this before).
'con'+'sole'='CONSOLE'
(Other definitions for console that I've seen before include "Comfort - control panel" , "Give comfort to (someone) for a loss" , "where the organist sits" , "Comfort - cabinet" , "Cheer in distress" .)