The most common and most likely answer to this crossword clue is the 7 letter word BRONZED
I've seen this crossword clue in The Guardian
B
R
O
N
Z
E
D
More clues leading to the result BRONZED
Buddy explains!

The straight part
We know that "12 across" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case 12 across = bronzed.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 BRONZED mean?
BRONZED verb- To plate with bronze.
- To color bronze; (of the sun) to tan.
- (of the skin) To change to a bronze or tan colour due to exposure to the sun.
- To make hard or unfeeling; to brazen.