unexpressive
unexp·res·sive
adjective
1.
deliberately impassive in manner
- “deadpan humor”
- “his face remained expressionless as the verdict was read”
Origin
From un- + expressive.
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.