The most common and most likely answer to this crossword clue is the 5 plus 4 letter word GREAT DANE
I've seen this crossword clue in The Guardian
G
R
E
A
T
D
A
N
E
More clues leading to the result GREAT DANE
- Read agent shot dog
- Large dog destroying tea garden
- D-day in teenager’s revision, needing an A for English
- This could be Andersen’s dog
- Hamlet‘s best friend?
- Serious Daphne essentially missing Scooby-Doo?
- Broadcast date range for TV’s Scooby-Doo
- It could be angered about a trespasser’s entry?
- Barking anger about projected leaving time? One … could be!
- A best friend of Kierkegaard, perhaps?
Buddy explains!
The straight part
We know that "One … could be" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one … could be = great dane.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.