The most common and most likely answer to this crossword clue is the 12 letter word LAMENTATIONS
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More clues leading to the result LAMENTATIONS
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The straight part
We know that "Old Testament book" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case old testament book = lamentations.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 LAMENTATIONS mean?
LAMENTATIONS noun- The act of lamenting.
- A sorrowful cry; a lament.
- Specifically, mourning.
- Lamentatio, (part of) a liturgical Bible text (from the book of Job) and its musical settings, usually in the plural; hence, any dirge
- A group of swans.