† Scottish. to say neither ba nor bum: to say nothing. Obsolete.Quot. 1749 is an example of bumv.2 1b used in a similar pattern of collocation of the same meaning.
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1749 Elegy Late Mass John T— xviii. 11 Ye're sitting there (quo' she) hum-drum, As ye could neither ba nor bum.]
1857 E. B. RamsayTwo Lect. on Some Changes in Social Life & Habits 22 They neither said ba nor bum.