Constant; unchanging
I believe the answer is:
stable
I believe this clue is a double definition.
'constant' is the first definition.
(associated in meaning)
'unchanging' is the second definition.
(I know that unchanging can be written as stable)
(Other definitions for stable that I've seen before include "Solid" , "uniform" , "Sound" , "far from bats?" , "Firmly fixed - home for horse" .)