The most common and most likely answer to this crossword clue is the 3 letter word HID
I've seen this crossword clue in Independent
H
I
D
More clues leading to the result HID
Buddy explains!
The straight part
We know that "Concealed" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case concealed = hid.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 HID mean?
HID verb- To put (something) in a place where it will be harder to discover or out of sight.
- To put oneself in a place where one will be harder to find or out of sight.