The most common and most likely answer to this crossword clue is the 6 letter word MISHIT
M
I
S
H
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T
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The straight part
We know that "False stroke" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case false stroke = mishit.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 MISHIT mean?
MISHIT noun- An incorrect or bad hit.
- To incorrectly or badly hit.