The most common and most likely answer to this crossword clue is the 10 letter word BOTTOMLESS
I've seen this crossword clue in The Guardian
B
O
T
T
O
M
L
E
S
S
More clues leading to the result BOTTOMLESS
- Unfathomable? A Midsummer Night’s Dream isn’t
- Infinite praise surrounding contrary maxim
- Order in vessels, small, very deep
- Unfathomable part in Shakespearean comedy? Not so
- No arse is profound
- Very deep saying recalled, amid praise
- A Midsummer Night’s Dream isn’t so unfathomable
- Immeasurable praise surrounding maxim recalled
Buddy explains!

The straight part
We know that "Very deep" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case very deep = bottomless.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 BOTTOMLESS mean?
BOTTOMLESS adjective- Having no bottom.
- Extremely deep.
- Having no bounds; limitless.
- Difficult to understand; unfathomable.
- Not wearing clothes below the waist; particularly not wearing clothes that would cover the genitalia.