bumpety-bump noun orbumpity-bump\see bumpety I\; orbumpety-bumpetyorbumpity-bumpity\| ̷ ̷ ̷ ̷ ̷ ̷| ̷ ̷ ̷ ̷ ̷ ̷\ Etymology: reduplication of bump (II) : an uneven jolting, thudding, or beating < the bumpety-bump of the wagon over the cobblestones > < the nervous bumpety-bumpety of his heart >