The most common and most likely answer to this crossword clue is the 9 letter word TWO-FACED
I've seen this crossword clue in Financial Times
T
W
O
-
F
A
C
E
D
Buddy explains!
The straight part
We know that "Describing many coins/not to be trusted" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case describing many coins/not to be trusted = two-faced.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 TWO-FACED mean?
TWO-FACED adjective- Having two faces or plane surfaces
- Deceitful, duplicitous
- Hypocritical