Funny how a command used to stop the horses (4)
I believe the answer is:
whoa
'command used to stop the horses' is the definition.
I can't tell whether this definition defines the answer.
'funny how a' is the wordplay.
'funny' indicates an anagram.
'how' with letters rearranged gives 'who'.
'who'+'a'='WHOA'
Can you help me to learn more?
(Other definitions for whoa that I've seen before include "Cry for horses to stop" , "horsy expression?" , "Opposite of "Giddy-up!"" , "Stop, Dobbin!" , "Command for horse to slow or stop" .)