The most common and most likely answer to this crossword clue is the 5 letter word TAWNY
I've seen this crossword clue in The Daily Telegraph
T
A
W
N
Y
Buddy explains!
The straight part
We know that "Light brown" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case light brown = tawny.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does TAWNY mean?
TAWNY noun- A light brown to brownish orange colour.
- Of a light brown to brownish orange color.
- A sweet, fortified wine which is blended and matured in wood.