Surprise cut short on river (6)

I believe the answer is:

amazon

'river' is the definition.
(Amazon is an example)

'surprise cut short on' is the wordplay.
'surprise' becomes 'amaze' (amazing is a kind of surprising).
'cut short' means to remove the last letter.
'amaze' with its last letter removed is 'amaz'.
'amaz'+'on'='AMAZON'

(Other definitions for amazon that I've seen before include "Encourage, ask" , "Strong, aggressive woman" , "Female warrior of Greek myth" , "Female warrior - parrot - South American river" , "Fighting woman from a great river" .)

I've seen this clue in The Telegraph and The Sun.

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.