Ignoble — HQ (4)
I believe the answer is:
base
I believe this clue is a double definition.
'ignoble' is the first definition.
(similar in meaning)
'hq' is the second definition.
(I've seen this before)
(Other definitions for base that I've seen before include "Foot; ignoble" , "Plinth" , "Foundation; counterfeit" , "floor" , "Bottom support" .)