An abrupt breaking-off in speech, often indicated in print using an ellipsis (…) or an em dash (—).

Avoidance of saying or reluctance to say too much; discretion, tight-lippedness; an instance of acting in this manner.

A silent and reserved nature.

Followed by of: discretion or restraint in the use of something.

To deliberately not listen or pay attention to; to disregard, to ignore.