The most common and most likely answer to this crossword clue is the 5 letter word LIBEL
I've seen this crossword clue in The Sunday Telegraph
L
I
B
E
L
More clues leading to the result LIBEL
- Ultimately, vitriol and bile stirred up calumny
- 'Some alcohol!' I belligerently slur
- False statement about British pound giving offence
- Offence produced by false statement about British learner
- Book that’s put in fake story initially liable for this?
- Defamation of politician artist’s not admiitted
- It might arise from some celeb I lampooned
- Generous to let artist escape for defamation
- Belli's case, perhaps!
- Defamation, I’ll be damned
Buddy explains!

The straight part
We know that "offence" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case offence = libel.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 LIBEL mean?
LIBEL noun- A written or pictorial false statement which unjustly seeks to damage someone's reputation.
- The act or crime of displaying such a statement publicly.
- Any defamatory writing; a lampoon; a satire.
- A written declaration or statement by the plaintiff of their cause of action, and of the relief they seek.
- A brief writing of any kind, especially a declaration, bill, certificate, request, supplication, etc.
- To defame someone, especially in a manner that meets the legal definition of libel.
- To proceed against (a ship, goods, etc.) by filing a libel.