The most common and most likely answer to this crossword clue is the 10 letter word EXERCISING
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Buddy explains!

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 EXERCISING mean?
EXERCISING verb- To exert for the sake of training or improvement; to practice in order to develop.
- To perform physical activity for health or training.
- To use (a right, an option, etc.); to put into practice.
- (now often in passive) To occupy the attention and effort of; to task; to tax, especially in a painful or vexatious manner; harass; to vex; to worry or make anxious.
- To set in action; to cause to act, move, or make exertion; to give employment to.
- The act by which something is exercised.