Cold girl turned round in waterway (5)
I believe the answer is:
canal
'waterway' is the definition.
(I know that canal is a type of waterway)
'cold girl turned round' is the wordplay.
'cold' becomes 'c' (eg on taps).
'girl' becomes 'lana' ().
'turned round' shows that the letters should be reversed in order.
'lana' reversed gives 'anal'.
'c'+'anal'='CANAL'
'in' acts as a link.
(Other definitions for canal that I've seen before include "Inland waterway" , "Grand Union perhaps" , "Man-made strip of water" , "Manmade flower" , "Passage" .)