The most common and most likely answer to this crossword clue is the 5 plus 4 letter word STRAW POLL
I've seen this crossword clue in The Times
S
T
R
A
W
P
O
L
L
More clues leading to the result STRAW POLL
- Blond politician on left's test of opinion
- In which to gauge the opinions of suckers?
- Show of preferences in walk nursing injured paw
- Primarily American white people splitting constitutional vote
- Does it collect the views of suckers?
- One checks opinion in walk round area with Penny
- Foreign Secretary once getting stick, it’s said, in unofficial vote
- Informal ballot gets Labour politician c-cut up
- Informal survey to win a drinking aid in the beginning
- Unofficial selection method for post-war reconstruction based on lives lost primarily...
Buddy explains!

The straight part
We know that "In which to gauge the opinions of suckers?" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case in which to gauge the opinions of suckers? = straw poll.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.