Unsmiling (adjective)

1. Not smiling or having a serious expression.
2. Not showing emotion or cheerfulness.

Origin:

From the old english word 'un' meaning 'not' and 'smile' meaning 'to smile'.

Examples:

1. The unsmiling face gave the impression of being unapproachable.
2. The unsmiling guard did not show any emotions.
3. The unsmiling audience gave no indication of their opinion.
4. The unsmiling CEO was not very approachable.
5. The unsmiling customer was not happy with the service.