The most common and most likely answer to this crossword clue is the 7 letter word WAVELET
I've seen this crossword clue in The Times
W
A
V
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More clues leading to the result WAVELET
Buddy explains!

The straight part
We know that "a ripple" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a ripple = wavelet.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 WAVELET mean?
WAVELET noun- A small wave; a ripple.
- A fast-decaying oscillation.