The most common and most likely answer to this crossword clue is the 8 letter word GARROTTE
I've seen this crossword clue in The Guardian
G
A
R
R
O
T
T
E
More clues leading to the result GARROTTE
- . Strangle fish with bad cut
- Killer pike, mostly decomposed
- Knotted garter to make instrument for executioner
- Would Stranglers perform hits with such an instrument?
- Put to death or turned into target for abuse
- Tease over mostly rubbish weapon
- Kill fish then tailless rat
- Use garter to strangle
- Stranglers perform hits with this instrument
- Assassinate or target revolutionary
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The straight part
We know that "instrument for executioner" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case instrument for executioner = garrotte.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.
Crossword Answer definitions
GARROTTE noun- A cord, wire or similar used for strangulation.
- An iron collar formerly used in Spain to execute people by strangulation.
- To execute by strangulation.
- To suddenly render insensible by semi-strangulation, and then to rob.