Beneath mountain peak, diverging trails wind (7)
I believe the answer is:
mistral
'wind' is the definition.
(mistral is a kind of wind)
'beneath mountain peak diverging trails' is the wordplay.
'beneath' means one lot of letters go next to another (in a down clue).
'peak' indicates taking the first letters (in a down clue, peak could mean the top letter).
'diverging' indicates an anagram (letters diverge from the original order).
The first letter of 'mountain' is 'm'.
'trails' anagrammed gives 'istral'.
'm' put next to 'istral' is 'MISTRAL'.
(Other definitions for mistral that I've seen before include "Strong cold dry wind" , "French wind" , "That's a blow" , "Violent northeast wind of southern France" , "A harsh blow" .)