The most common and most likely answer to this crossword clue is the 8 letter word CURRENCY
C
U
R
R
E
N
C
Y
Buddy explains!

The straight part
We know that "cash" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cash = currency.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 CURRENCY mean?
CURRENCY noun- Money or other items used to facilitate transactions.
- (more specifically) Paper money.
- The state of being current; general acceptance or recognition.
- Current value; general estimation; the rate at which anything is generally valued.
- Fluency; readiness of utterance