unintentional
Something that is unintentional is not done deliberately, but happens by accident. adj
(=inadvertent)
Perhaps he had slightly misled them, but it was quite unintentional..., There are moments of unintentional humour.
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unintentionally adv ADV adj, ADV with v
...an overblown and unintentionally funny adaptation of `Dracula'., ...a scientist who unintentionally absorbed a small quantity of the mind-altering drug through the skin on his fingers.