The most common and most likely answer to this crossword clue is the 8 letter word UNDERSEA
U
N
D
E
R
S
E
A
More clues leading to the result UNDERSEA
- German and Irish article, deep, in the main?
- Submarine needs anti-rust treatment endlessly
- Craft used near submarine
- Submarine manoeuvres ensured opening for Allies
- Trained end user with a submarine
- Endures a tour in submarine
- Endures being torpedoed by a submarine
- At sea endures a submarine
- Before echo sounders, so lost on a submarine
- Submarine inside founders easily
Buddy explains!

The straight part
We know that "submarine" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case submarine = undersea.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 UNDERSEA mean?
UNDERSEA adjective- Existing, relating to, or made for use beneath the sea.