To bump, strike repeatedly, or jolt about; to jostle (Scottish dialect).
Possibly a frequentative or intensive form of 'dunt', with the -le suffix (which often creates verbs meaning repeated or continuous action). This type of modification is common in Scottish English.
Scottish has a genius for making words that sound like what they mean—'duntle' sounds jerkier and more chaotic than 'dunt,' which is exactly what the extra syllable does to the meaning, making morphology and onomatopoeia work together.
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