peremptory in WordNet English dictionary

1. offensively self-assured or given to exercising usually unwarranted power
   "an autocratic person"; "autocratic behavior"; "a bossy way of ordering others around"; "a rather aggressive and dominating character"; "managed the employees in an aloof magisterial way"; "a swaggering peremptory manner"
   autocratic  bossy  dominating  high-and-mighty  magisterial  peremptory 
   
2. putting an end to all debate or action
   "a peremptory decree"
   peremptory 
   
3. not allowing contradiction or refusal
   "spoke in peremptory tones"; "peremptory commands"
   peremptory