The most common and most likely answer to this crossword clue is the 7 letter word SINNERS
I've seen this crossword clue in Financial Times
S
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More clues leading to the result SINNERS
Buddy explains!

The straight part
We know that "Offenders" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case offenders = sinners.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 SINNERS mean?
SINNERS noun- A person who sins or has sinned.
- A person who sins or has sinned by the action or identity indicated or previously mentioned
- An unregenerate person.
- (figuratively, by extension) A person with negative qualities; one who does bad things.