disfluency Definition

an involuntary disruption in the flow of speech that may occur during normal childhood development of spoken language or during normal adult speech but is most often symptomatic of a speech impairment; especially : a disorder of vocal communication that is marked by frequent involuntary disruption or blocking of speech (as by repetition of all or part of a word or by prolonging vocal sounds) and typically has an onset during childhood : stuttering

an act or instance of disfluency : stutter