Order to dismiss or fire all but the last (4)
I believe the answer is:
shoo
'order to dismiss' is the definition.
I can't judge whether this definition defines the answer.
'fire all but the last' is the wordplay.
'fire' becomes 'shoot' (shooting is a kind of firing).
'all but the last' means to remove the last letter.
'shoot' with its last letter taken off is 'SHOO'.
'or' acts as a link.
Can you help me to learn more?
(Other definitions for shoo that I've seen before include "Push off" , "Get lost!" , "Go away quickly!" , "used to scare away animals" , "Expression to chase away an animal" .)