The Collaborative International Dictionary of English v.0.48:

Bossism \Boss"ism\, n.
   The rule or practices of bosses, esp. political bosses.
   [Slang, U. S.]
   [1913 Webster]

WordNet (r) 3.0 (2006):

bossism
    n 1: domination of a political organization by a party boss

Moby Thesaurus II by Grady Ward, 1.0:

40 Moby Thesaurus words for "bossism":
   Machtpolitik, Realpolitik, Tammany Hall, arbitrariness,
   authoritarianism, authoritativeness, autocraticalness,
   career politics, confrontation politics, consensus politics,
   domineering, domineeringness, economics in action,
   empirical politics, imperativeness, imperiousness,
   kid-glove politics, lordliness, machine politics, magisterialness,
   magistrality, masterfulness, overbearance, overbearing,
   overbearingness, partisan politics, partisanism, peanut politics,
   peremptoriness, petty politics, politics, polity,
   pork-barrel politics, power politics, practical politics,
   pressure-group politics, reform politics, silk-stocking politics,
   tyrannicalness, ward politics