The most common and most likely answer to this crossword clue is the 7 letter word USEABLE
I've seen this crossword clue in The Daily Telegraph
U
S
E
A
B
L
E
More clues leading to the result USEABLE
- Movement in blue sea could get you fit
- Blue liquid ready to be applied
- In bakehouse a blender’s handy
- American English sailor with the French may be of service
- Fitting handle takes expert
- . American English, being clever, may be of service
- Blue sea waves at your disposal
- Blue novel about marine in service
Buddy explains!

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 USEABLE mean?
USEABLE adjective- Capable of being used.
- Easy to use; exhibiting good usability.
- Homosexual