Quick nap in the office (6)
I believe the answer is:
presto
'quick' is the definition.
(I've seen this before)
'nap in the office' is the wordplay.
'nap' becomes 'rest'.
'in the' indicates putting letters inside.
'office' becomes 'po' (I can't justify this - if you can you should give a lot more credence to this answer).
'rest' going into 'po' is 'PRESTO'.
Can you help me to learn more?
(Other definitions for presto that I've seen before include "Immediately" , "Hey . . . . ., says the magician (6)" , "quickly in bars" , "hey......,cries the magician" , "To be played quickly" .)