taciturn
Quiet and usually speaking very little.
Taciturn describes someone who naturally speaks very little. A taciturn person prefers silence to conversation, choosing their words carefully and speaking only when they have something specific to say. They answer questions briefly and rarely volunteer extra information or small talk.
You might have a taciturn grandfather who sits contentedly at family dinners, listening to everyone's chatter while only occasionally contributing a short comment. Or perhaps there's a taciturn student in your class who does excellent work but never raises their hand unless called on, and even then answers in just a few words.
The word specifically describes someone's usual nature, not just a quiet moment. Everyone has times when they don't feel like talking, but a taciturn person consistently chooses few words over many. This isn't rudeness: taciturn people often think carefully before speaking and say exactly what they mean when they do talk.
Being taciturn is different from being unfriendly. Many taciturn people are warm and caring; they simply express themselves through actions rather than words. They're the friend who shows up to help you move without making a big speech about it, or the teammate who quietly does their job while others celebrate loudly.