overmaster \ˌ ̷ ̷ ̷ ̷ˈ ̷ ̷ ̷ ̷\transitive verb Etymology: Middle English overmaistren, from over (I) + maistren to master 1.: to establish mastery over : subdue, vanquish < the sensation overmastered me completely — Rudyard Kipling > 2.obsolete: to be master over