The most common and most likely answer to this crossword clue is the 7 letter word FLICKER
I've seen this crossword clue in The Guardian
F
L
I
C
K
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More clues leading to the result FLICKER
Buddy explains!
The straight part
We know that "Loud user of tongue in a flash (7)/a flash" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case loud user of tongue in a flash (7)/a flash = flicker.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 FLICKER mean?
FLICKER noun- An unsteady flash of light.
- A short moment.
- To burn or shine unsteadily, or with a wavering light.
- To keep going on and off; to appear and disappear for short moments; to flutter.
- To flutter; to flap the wings without flying.
- Any of certain small woodpeckers, especially of the genus Colaptes.
- One who flicks.