The most common and most likely answer to this crossword clue is the 7 letter word EXCLUDE
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The straight part
We know that "Leave out" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case leave out = exclude.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 EXCLUDE mean?
EXCLUDE verb- To bar (someone) from entering; to keep out.
- To expel; to put out.
- To omit from consideration.
- To refuse to accept (evidence) as valid.
- To eliminate from diagnostic consideration.