The most common and most likely answer to this crossword clue is the 11 letter word RESPIRATION
I've seen this crossword clue in Financial Times
R
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S
P
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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 RESPIRATION mean?
RESPIRATION noun- The process of inhaling and exhaling; breathing, breath.
- An act of breathing; a breath.
- Any similar process in an organism that lacks lungs that exchanges gases with its environment.
- The process by which cells obtain chemical energy by the consumption of oxygen and the release of carbon dioxide.