One that's cold to walk over (6)
I believe the answer is:
icecap
'one that's cold to walk over' is the definition.
I can't tell whether this definition defines the answer.
'one that's cold to walk over' is the wordplay.
'one' becomes 'I' (Roman numeral).
'that's cold' becomes 'c' (eg on taps).
'to walk' becomes 'pace' (pacing is a kind of walking).
'over' says the letters should be written in reverse.
'pace' back-to-front is 'ecap'.
'i'+'c'+'ecap'='ICECAP'
Can you help me to learn more?
(Other definitions for icecap that I've seen before include "Frozen polar area" , "Snowy mountain peak" , "Area round pole" , "Frozen topping" , "Permanently frozen covering of land" .)