Study in The Observer (7)
I believe the answer is:
monitor
'study' is the definition.
(thesaurus)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for monitor that I've seen before include "Prefect; a loudspeaker" , "Keep a check on" , "Check on - large lizard" , "A television or computer screen" , "Keep under surveillance" .)