The most common and most likely answer to this crossword clue is the 4 letter word MERE
I've seen this crossword clue in The Daily Telegraph
M
E
R
E
Buddy explains!

The straight part
We know that "bare" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case bare = mere.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 MERE mean?
MERE noun- A body of standing water, such as a lake or a pond. More specifically, it can refer to a lake that is broad in relation to its depth. Also included in place names such as Windermere.
- Boundary, limit; a boundary-marker; boundary-line.
- To limit; bound; divide or cause division in.
- To set divisions and bounds.
- To decide upon the position of a boundary; to position it on a map.
- Famous.
- Pure, unalloyed .
- Nothing less than; complete, downright .
- Just, only; no more than , pure and simple, neither more nor better than might be expected.
- A Maori war-club.