/ ɪmˈpɪəriəs; NAmE -ˈpɪr-/ adjective
( formal ) expecting people to obey you and treating them as if they are not as important as you :
an imperious gesture / voice / command
► im·peri·ous·ly adverb :
'Get it now,' she demanded imperiously.
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WORD ORIGIN
mid 16th cent.: from Latin imperiosus , from imperium command, authority, empire; related to imperare to command. Compare with imperial .