Incoherent/ˌɪnkəʊˈhɪrənt,ˌɪnkəʊˈherənt/ Definition 1 of 3Pro Tip 1/3Clarity Matters Use 'incoherent' to describe unclear communication that's hard to comprehend. The lecture was incoherent, leaving many students bewildered. Pro Tip 2/3Speech Impediment 'Incoherent' can refer to speech that's unclear due to a speaker's impairment or distress. After the accident, his speech was slurred and incoherent. Pro Tip 3/3Emotional State An emotional state can make someone's words incoherent, not just language ability. Overwhelmed with grief, she uttered incoherent pleas.