The most common and most likely answer to this crossword clue is the 13 letter word INCORRUPTIBLE
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More clues leading to the result INCORRUPTIBLE
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The cryptic/wordplay part
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What does INCORRUPTIBLE mean?
INCORRUPTIBLE noun- One of an ancient religious sect of Alexandria, whose adherents believed that the body of Christ was incorruptible, and that he suffered hunger, thirst, and pain only in appearance.
- Incapable of being bribed or morally corrupted; inflexibly just and upright.
- Not subject to corruption or decay.