The most common and most likely answer to this crossword clue is the 4 letter word GLIM
G
L
I
M
More clues leading to the result GLIM
Buddy explains!

The straight part
We know that "light" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case light = glim.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 GLIM mean?
GLIM noun- Brightness; splendour
- A light; a candle; a lantern; a fire.
- An eye.
- A pair of glasses or spectacles.
- A look; a glimpse.
- Gonorrhea
- Fake documents claiming the loss of property by fire (for use in begging).
- To brand on the hand.
- To illuminate.
- To see; to observe.