The most common and most likely answer to this crossword clue is the 4 plus 6 letter word GOLD DIGGER
I've seen this crossword clue in The Daily Telegraph
G
O
L
D
D
I
G
G
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R
More clues leading to the result GOLD DIGGER
Buddy explains!
The straight part
We know that "she’s after rich mate" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case she’s after rich mate = gold digger.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 GOLD DIGGER mean?
GOLD DIGGER noun- Someone who digs or mines for gold.
- A person (usually female) who cultivates a personal relationship in order to attain wealth.