The most common and most likely answer to this crossword clue is the 5 letter word WADED
I've seen this crossword clue in The Daily Telegraph
W
A
D
E
D
Buddy explains!

The straight part
We know that "paddled through water" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case paddled through water = waded.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 WADED mean?
WADED verb- To walk through water or something that impedes progress.
- To progress with difficulty
- To walk through (water or similar impediment); to pass through by wading
- To enter recklessly.