The most common and most likely answer to this crossword clue is the 8 letter word DANCETTE
D
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The straight part
We know that "Line that’s jagged" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case line that’s jagged = dancette.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 DANCETTE mean?
DANCETTE noun- A zigzag or indented line or figure.
- The chevron or zigzag moulding common in Romanesque architecture.