The most common and most likely answer to this crossword clue is the 10 letter word DEPRECIATE
D
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P
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C
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A
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More clues leading to the result DEPRECIATE
- I must go in to protest against decline
- Strongly disapprove of accepting current fall in value
- One included in censure is to lose value
- Time to stockpile drug before trading price leads to fall in value
- Speak ill of one taken in by decrease in value
- Deplore welcoming Independent’s fall in value
- Ultimately decrease in price, deteriorating in time?
- Disapprove of hiding current drop in value
- Write down rubbish ape recited
- Protest against absorbing current fall in value
Buddy explains!

The straight part
We know that "decline" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case decline = depreciate.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 DEPRECIATE mean?
DEPRECIATE verb- To lessen in price or estimated value; to lower the worth of.
- To decline in value over time.
- To belittle or disparage.