The most common and most likely answer to this crossword clue is the 13 letter word INTERROGATIVE
I've seen this crossword clue in The Daily Telegraph
I
N
T
E
R
R
O
G
A
T
I
V
E
Buddy explains!

The straight part
We know that "raising questions" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case raising questions = interrogative.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 INTERROGATIVE mean?
INTERROGATIVE noun- (grammar) A word (pronoun, pronominal adjective, or adverb) implying interrogation, or used for asking a question: why, who, when, etc.
- A question; an interrogation.
- (grammar) Asking or denoting a question: as, an interrogative phrase, pronoun, or point.
- Pertaining to inquiry; questioning
- The punctuation mark "?", used at the end of a sentence to indicate a question.
- A state of doubt or uncertainty.
- An enigmatic, inscrutable, or mysterious person or thing; an enigma, a riddle.
- Polygonia interrogationis, a North American nymphalid butterfly with a silver mark on the underside of its hindwing resembling a question mark (sense 1).