The most common and most likely answer to this crossword clue is the 7 letter word OPIOIDS
I've seen this crossword clue in Independent
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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 OPIOIDS mean?
OPIOIDS noun- A substance that has effects similar to opium.
- Any of the natural substances, such as an endorphin, released in the body in response to pain.
- Any of a group of synthetic compounds that exhibit similarities to the opium alkaloids that occur in nature.