The most common and most likely answer to this crossword clue is the 6 plus 4 letter word TRENCH COAT
I've seen this crossword clue in The Daily Telegraph
T
R
E
N
C
H
C
O
A
T
More clues leading to the result TRENCH COAT
- Hector can’t change into outerwear
- Garment with awfully neat crotch
- Technocrat redesigned form of protection
- Waterproof garment swimming coach put in river
- Dick’s classic garb misleads technocrat
- In river, coach ruined garment
- Outdoor garment husband wears at concert that rocks
- What might be worn by eccentric technocrat?
- Waterproof jacket technocrat ordered
- Technocrat ordered outdoor garment
Buddy explains!
The straight part
We know that "This’ll keep the water off" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case this’ll keep the water off = trench coat.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.