BOSSIEST
Scrabble letter values: B3O1S1S1I1E1S1T1 = 10
Definition
BOSSIEST is the superlative of BOSSY.
adjective BOSSY: offensively self-assured or given to exercising usually unwarranted power.
Synonyms of BOSSY: autocratic, dominating, high-and-mighty, magisterial, peremptory