The most common and most likely answer to this crossword clue is the 6 letter word SUNLIT
I've seen this crossword clue in The Times
S
U
N
L
I
T
More clues leading to the result SUNLIT
- Bright students turning away from books
- Illuminated sign colonel finally installed in clubs, perhaps
- Small group welcoming learner, naturally bright
- Given light by setter?
- Non-illuminated bend up front leads to the opposite
- Small group surrounds pupil enlightened by star
- Bright day left one burnt at the end
- Small, dark and bright
- Sombre at first and dark, but not in shadow
- South in the dark when the north is this
Buddy explains!

The straight part
We know that "Illuminated" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case illuminated = sunlit.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 SUNLIT mean?
SUNLIT adjective- Illuminated by sunlight.