One forbidden to indulge when in office? (6)
I believe the answer is:
smoker
'office?' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for smoker that I've seen before include "part of train once" , "one cures" , "User of cigarettes" , "Puffer" , "One who enjoys a cigar?" .)