The most common and most likely answer to this crossword clue is the 8 letter word SHEATHED
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More clues leading to the result SHEATHED
Buddy explains!

The straight part
We know that "Covered" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case covered = sheathed.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 SHEATHED mean?
SHEATHED verb- To put (something such as a knife or sword) into a sheath.
- To encase (something) with a protective covering.
- Of an animal: to draw back or retract (a body part) into the body, such as claws into a paw.
- To thrust (a sharp object like a sword, a claw, or a tusk) into something.
- To abandon or cease (animosity, etc.)
- To provide (a sword, etc.) with a sheath.
- To relieve the harsh or painful effect of (a drug, a poison, etc.).