The most common and most likely answer to this crossword clue is the 3 plus 4 letter word RED FLAG
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More clues leading to the result RED FLAG
- Instruction to halt touching case of deaf prisoner
- Look embarrassed to lose energy, a warning sign
- Signal judge harbouring Dutch convict
- Alert that’s raised by socialists?
- Signal to stop flushed German fellow climbing
- Blushing, decline to be symbol of revolution
- Warning raised by the Turks?
- Standard stop signal in song
- Doctor fled in torment warning of danger
- Standard wine label
Buddy explains!

The straight part
We know that "symbol of revolution" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case symbol of revolution = red flag.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.