17 down
Runner
is
prepared
to
tackle
1K
(3)
Runner is prepared to tackle 1K (3)
hints
0
checks
0
hints
The definition is at the beginning of the clue.
How the clue works
The definition here is Runner, meaning something that glides along snow. You rearrange 'is' (flagged by 'prepared') to get SI, then stuff K (the single K from '1K') inside it, giving you the answer.