roister UK /ˈɹɔɪstə/US /ˈɹɔɪstɚ/noun 2verb 2forms 3 noun2 •(no longer used) A session of noisy, drunken, or riotous behaviour.The servants went out on the roister after getting paid. •(no longer used) A roisterer.He now suspected that the grave roysters of the mountain had put a trick on him, and having dosed him with liquor, had robbed him of his gun. — 1819 verb2 •To engage in noisy, drunken, or riotous behaviour.He loved Rick and gave the best years of his life, now to roistering with him, now to hanging on to his coat-tails. — 1986 •To walk with a swaying motion. formsroistered · roistering · roisters