Study’s a bit of a burden (3)
I believe the answer is:
den
'study's' is the definition.
(term for a study or office)
'a bit of a burden' is the wordplay.
'DEN' is hidden within the letters.
But, I'm unsure how this is indicated.
Can you help me to learn more?
(Other definitions for den that I've seen before include "Wild animal's lair" , "Home of the beast" , "Hiding place" , "Cave" , "Gentleman's study or animal's lair" .)