aposiopestic
/ˌæpəsaɪˈɒpɪstɪk/Definitions
1. adjective
relating to or characterized by the act of stopping or pausing in speech
“The aposiopestic effect is often used in poetry to create a dramatic pause before the final line.”
2. noun
a pause or interruption in speech, especially one that is deliberately made for effect
“The aposiopestic moment in the play was where the actor suddenly stopped speaking to emphasize a point.”