Crossword Genius

Onset of rain stops wet Perth Test (4)

Ross

I believe the answer is:

pree

I'm a little stuck... Click here to teach me more about this clue!

'test' is the definition.
(I've seen this before)

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Another definition for pree that I've seen is " At Gretna Green, test by kissing".)

I've seen this clue in The Times and The Sunday Times.
Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.