peremptory

adjectives

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
not allowing contradiction or refusal
"spoke in peremptory tones"; "peremptory commands"
peremptory
is similar to
requiring attention or action
"as nuclear weapons proliferate, preventing war becomes imperative"; "requests that grew more and more imperative"
imperative
putting an end to all debate or action
"a peremptory decree"
peremptory
is similar to
determining or having the power to determine an outcome
"cast the decisive vote"; "two factors had a decisive influence"
decisive