The most common and most likely answer to this crossword clue is the 7 plus 3 letter word CASPIAN SEA
C
A
S
P
I
A
N
S
E
A
More clues leading to the result CASPIAN SEA
- Water recycled as in space, prime requirement for astronauts
- Rearrange a space as in inland lake
- Panic as drunken European interrupts odd bits of Swan Lake
- Body of water, fluid Asian 2?
- Cape Asian’s remapped discovering this sea
- Asians pace about large water body
- Manoeuvre as in space over a water body
- Free space, as in a large body of water
Buddy explains!

The straight part
We know that "sea" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case sea = caspian sea.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.