Sierra Nevada lake (5)
I believe the answer is:
tahoe
'sierra nevada lake' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for tahoe that I've seen before include "Nevada/California lake" , "the Nevada/California border area" , "Lake in Sierra Nevada mountains" , "Lake/desert resort on the California-Nevada border" , "Mountain lake" .)