The most common and most likely answer to this crossword clue is the 4 plus 5 letter word BASE METAL
B
A
S
E
M
E
T
A
L
More clues leading to the result BASE METAL
- Corrupt spy chief and others lead for example
- A meal best canned in tin, say
- 6 is a degree over excited Maltese
- Maybe lead me into group in embrace of fertility god
- Swiss city defends rotten meat in tin, for instance
- Sailor turned up with new Maltese 19, for example
- Tee off with 17d’s iron?
- In Swiss city, police requiring a copper, possibly?
- Lead, say from corrupt copper?
- Lead for one lame beast needs adjusting
Buddy explains!

The straight part
We know that "copper, possibly" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case copper, possibly = base metal.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.