Climber's companion putting cold water on fire (3,3)
I believe the answer is:
ice axe
'climber's companion' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'cold water on fire' is the wordplay.
'cold water' becomes 'ice'.
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'fire' becomes 'axe' (I've seen this in another clue).
'ice'+'axe'='ICE-AXE'
'putting' is the link.
Can you help me to learn more?
(Other definitions for ice axe that I've seen before include "Climber's tool" , "which a climber may use" , "Mountaineer's equipment" , "SW London area" , "Mountaineer's tool" .)