The most common and most likely answer to this crossword clue is the 9 letter word DECIDEDLY
I've seen this crossword clue in The Guardian
D
E
C
I
D
E
D
L
Y
Buddy explains!
The straight part
We know that "Without question!" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case without question! = decidedly.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 DECIDEDLY mean?
DECIDEDLY adverb- In a manner which leaves little question; definitely, clearly.
- In a decided or final manner; resolutely.