high-and-mighty
     adj : 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" [syn: {autocratic}, {bossy},
            {dominating}, {magisterial}, {peremptory}]
Source: WordNet® 2.0