Retiring policeman’s maintaining place without much upstairs (6)
I believe the answer is:
stupid
'without much upstairs' is the definition.
I can't judge whether this defines the answer.
'retiring policeman's maintaining place' is the wordplay.
'retiring' is a reversal indicator.
'policeman's' becomes 'di's' (detective inspector).
'maintaining' means one lot of letters goes inside another (inserted letters are held or maintained).
'place' becomes 'put' (synonyms).
'dis' enclosing 'put' is 'diputs'.
'diputs' back-to-front is 'STUPID'.
Can you help me to learn more?
(Other definitions for stupid that I've seen before include "Daft" , "Idiot" , "Barmy" , "Unintelligent, really thick" , "Asinine" .)