Hurried up, pinching police officer’s bottom (5)
I believe the answer is:
nadir
'bottom' is the definition.
(I've seen this before)
'hurried up pinching police officer's' is the wordplay.
'hurried' becomes 'ran' (running is a kind of hurrying).
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'pinching' means one lot of letters goes inside another (taking inside).
'police officer' becomes 'DI' (detective inspector).
'ran' written backwards gives 'nar'.
'nar' enclosing 'di' is 'NADIR'.
(Other definitions for nadir that I've seen before include "Low point" , "Drain into the lowest point (5)" , "It's the depths" , "most unsuccessful point" , "lowest of the low" .)