The most common and most likely answer to this crossword clue is the 11 letter word ENGINEERING
I've seen this crossword clue in The Times
E
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Buddy explains!

The straight part
We know that "Devising" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case devising = engineering.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 ENGINEERING mean?
ENGINEERING verb- To design, construct or manage something as an engineer.
- To alter or construct something by means of genetic engineering.
- To plan or achieve some goal by contrivance or guile; to wangle or finagle.
- To control motion of substance; to change motion.
- To work as an engineer.
- The application of mathematics and the physical sciences to the needs of humanity and the development of technology.
- The area aboard a ship where the engine is located.
- Actions controling the motion, shape, and/or substance of any physical object(s).
- Designates office area of the professional engineering staff.