aposiopesis
An abrupt breaking-off in speech, often indicated in print using an ellipsis (…) or an em dash (—).
countable, uncountable
—"My ſiſter, mayhap," quoth my uncle Toby, "does not chooſe to let a man come ſo near her ****" Make this daſh—'tis an Apoſiopeſis.—Take the daſh away, and write Backſide,—'tis Bawdy.
Where it comes from
From Latin aposiopesis, from Ancient Greek ἀποσιώπησις (aposiṓpēsis), from ἀποσιωπάω (aposiōpáō, “be silent”), from ἀπό (apó, “off, from”) + σιωπάω (siōpáō, “to be silent”).
Adapted from the Wiktionary entry aposiopesis (CC BY-SA 4.0).