The most common and most likely answer to this crossword clue is the 7 letter word SUNLESS
I've seen this crossword clue in The Sunday Telegraph
S
U
N
L
E
S
S
More clues leading to the result SUNLESS
- Seedling's beginning, except in permanent shadow
- Stimulating originally, if not dull
- We hear no father to boys is gloomy
- Gloomy as newspaper’s been taken?
- Dark except when sierra is to the west
- Head of silver, if not grey
- Shadow’s emerging, except if — this?
- First in school, except when not bright, naturally
- Sombre at first if not gloomy
- Gloomy unless tailing a bit of skirt
Buddy explains!
The straight part
We know that "dark" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case dark = sunless.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 SUNLESS mean?
SUNLESS adjective- Without the sun or sunshine; shaded; shadowed.
- Dreary, cheerless.