The most common and most likely answer to this crossword clue is the 6 letter word FLOATY
F
L
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More clues leading to the result FLOATY
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 = floaty.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 FLOATY mean?
FLOATY noun- A lilo or similar item that floats on water and can be sat on.
- A particle of food, etc. found floating in liquid.
- Buoyant, tending to float on a liquid or rise in air or gas
- (of a dress) lightweight, so as to rise when the wearer is walking.
- Light, hypnotic and relaxing.
- Having a feeling of extreme calm, as if floating through the air.