ebullitive

Example:The dour old man never grinned, no matter what was going on around him.

Definition:Characterized by a grim or sullen disposition; gloomy and uncommunicative.

Example:The staid businessman preferred to keep his opinions to himself rather than share his views with everyone.

Definition:Characterized by or conforming to conventional and conservative principles of conduct; sober in manner or color; not brilliant or ornamental.

Example:She was a reserved young lady, comfortable with her workmates but saving her joy in her family.

Definition:Restrained in manner or behavior; holding back.