The most common and most likely answer to this crossword clue is the 8 letter word GLOAMING
I've seen this crossword clue in The Daily Telegraph
G
L
O
A
M
I
N
G
More clues leading to the result GLOAMING
Buddy explains!
The straight part
We know that "twilight" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case twilight = gloaming.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 GLOAMING mean?
GLOAMING noun- Twilight, as at early morning (dawn) or (especially) early evening; dusk.
- Sullenness; melancholy.