peremptory

Concise Oxford English Dictionary © 2008 Oxford University Press:
peremptory /pəˈrɛm(p)t(ə)ri, ˈpɛrɪm-/

▶adjective

• 1 insisting on immediate attention or obedience; brusque and imperious.

• 2 Law not open to appeal or challenge; final.

– derivatives
peremptorily adverb,
peremptoriness noun.

– origin ME: via Anglo-Norman Fr. from L. peremptorius ‘deadly, decisive’, from perempt-, perimere ‘destroy, cut off’.