The most common and most likely answer to this crossword clue is the 7 letter word TASERED
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The straight part
We know that "Sedater criminal thus?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sedater criminal thus? = tasered.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 TASERED mean?
TASERED verb- To shock a person, thing, individual, or animal with a handheld device with the electric shock that it delivers; to stun with a stun gun.
- To strike verbally or gesturally with ill intents.