Kid given detention by lecturer, monster! (6)
I believe the answer is:
dragon
'monster' is the definition.
(dragon is a kind of monster)
'kid given detention by lecturer' is the wordplay.
I cannot quite see how this works, but
'kid' could be 'rag' (both can mean to tease) and 'rag' is found in the answer.
'lecturer' could be 'don' (don can mean an academic) and 'don' is present in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for dragon that I've seen before include "Fire-breathing beast" , "Fire-breathing creature slain by St George" , "Fire breathing mythological creature" , "Fiery reptile or person" , "Fail tediously to conclude" .)