Good, slow down to prepare for ice (4)
I believe the answer is:
grit
'ice' is the definition.
The answer and definition can be both substances as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'good slow down to prepare' is the wordplay.
I cannot really understand how this works, but
'good' could be 'g' (abbreviation) and 'g' is located in the answer.
The remaining letters 'rit' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'for' is the link.
Can you help me to learn more?
(Other definitions for grit that I've seen before include "Small hard particles - determination" , "Small particles of stone or sand" , "Small hard particles - courage" , "Particles of stone/sand" , "Fragments to sprinkle on roads" .)