Cryptic crossword clue
Depression's limiting quiet individual, they’ll testify 9

The most common and most likely answer to this crossword clue is the 9 letter word DEPONENTS

I've seen this crossword clue in The Times
D
E
P
O
N
E
N
T
S

Buddy explains!

The straight part
We know that "they’ll testify" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they’ll testify = deponents.
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 DEPONENTS mean?

DEPONENTS noun
  1. A witness; especially one who gives information under oath, in a deposition concerning facts known to him or her.
  2. (grammar) A deponent verb.

Latest crossword clues with full explanations