IPA: /ˌɪn.kəʊˈhɪə.rənt/
KK: /ɪnkoʊˈhɪrənt/
Not able to be understood clearly; lacking logical connection or order.
His explanation was so incoherent that no one could follow his argument.
Incoherent → It is formed from "in-" (meaning not) and "cohaerere" (meaning to stick together or to be connected). The word "incoherent" describes something that is not logically connected or lacks clarity.
Think of 'not' ('in-') being connected ('cohaerere') — that's why incoherent means something that doesn't stick together logically.