pe ‧ remp ‧ to ‧ ry /pəˈrempt ə ri/ BrE AmE adjective formal
[ Date: 1200-1300 ; Language: Latin ; Origin: peremptorius , from perimere 'to take completely, destroy' ]
peremptory behaviour, speech etc is not polite or friendly and shows that the person speaking expects to be obeyed immediately:
a peremptory demand for silence
—peremptorily adverb