Busy topping up the bottom drawer? (7)
I believe the answer is:
engaged
'busy' is the definition.
(similar in meaning)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for engaged that I've seen before include "Fully committed - to get married?" , "Occupied with business - about to marry?" , "Promised in marriage" , "Started to fight" , "Bound by promise" .)