untalkative

He seemed determined to be uninteresting and untalkative.

And the notoriously untalkative De Niro was downright chatty when it came to talking about his longtime collaborator.

Why is a person wearing one black glove pushing a big suitcase in an airport any more suspicious than an untalkative man on a plane scribbling unrecognizable text in a notebook?

Once on the Sam Simon, the Thunder’s officers were surly and untalkative.

Dolly, for once untalkative, had not paid attention to this conversation; the moon had risen, and she had been watching its radiance descend slowly and make a silver path across the river.