Light brown mist swirling until one's lost (8)
I believe the answer is:
hazelnut
'light brown' is the definition.
Although both the answer and definition are singular nouns, I cannot see how one could define the other.
'mist swirling until one's lost' is the wordplay.
'mist' becomes 'haze' (haze can mean a mist).
'swirling' is an anagram indicator.
'one' becomes 'i' (Roman numeral).
'lost' is a deletion indicator.
'until' with 'i' taken away is 'untl'.
'untl' with letters rearranged gives 'lnut'.
'haze'+'lnut'='HAZELNUT'
Can you help me to learn more?
(Other definitions for hazelnut that I've seen before include "Cobnut or filbert" , "Filbert or cob" .)