The most common and most likely answer to this crossword clue is the 10 letter word BLISTERING
I've seen this crossword clue in Financial Times
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Buddy explains!

The straight part
We know that "Very quick" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case very quick = blistering.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 BLISTERING mean?
BLISTERING verb- To raise blisters on.
- To have a blister form.
- To criticise severely.
- To break out in blisters.
- The practice of forming blisters on the skin, to promote blood flow and aid healing.
- Causing blisters
- Very hot
- Harsh or corrosive
- Scornful
- Very fast