Teacher's pet, perhaps wasting time (5)
I believe the answer is:
rabbi
'teacher's' is the definition.
(I've seen this before)
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rabbi that I've seen before include "Religious person" , "Hebrew scholar" , "Leader of worshippers" , "Religious leader in a Jewish community" , "Jewish minister" .)