One-word substitution (personality trait: speaking habits): Identify the precise adjective for someone who is habitually silent or speaks very little. Context: The term should denote consistent brevity or reluctance in speech, not mere clarity or neutrality. Instruction: Choose the best single-word substitute from the list.

Given data

• Definition target: habitually silent / speaking little.
• Options: Taciturn, Servile, Unequivocal, Synoptic.

Concept / Approach
Taciturn = reserved, habitually silent. Other options denote different qualities (submissive, clear, summarized).

Elimination
Taciturn — quiet by habit; correct. ✅Servile — overly submissive; unrelated to speech volume. ❌Unequivocal — clear, unambiguous; about meaning, not talkativeness. ❌Synoptic — giving a brief summary; describes texts, not people's speaking habits. ❌

Verification / Example
‘‘A taciturn colleague who rarely volunteers comments in meetings.’’

Final Answer
Taciturn