Question one: What might be said to end a ride? (4)

I believe the answer is:
whoa
'might be said to end a ride?' is the definition.
I can't judge whether this defines the answer.
'question one' is the wordplay.
'question' becomes 'who' (who is a question word).
'one' becomes 'a' (a thing is one thing).
'who'+'a'='WHOA'
'what' is the link.
Can you help me to learn more?
(Other definitions for whoa that I've seen before include "The King of rock and roll" , "Opposite of "Giddy-up!"" , "Stop, Dobbin!" , "Command for horse to slow or stop" , "halt" .)
