Topic: Substitution, Expression, & Definition,

Best Answer Explained in Below-:

The term "taciturn" specifically refers to a person who is habitually silent or speaks very little. Originating from the Latin word "tacitus," which means "silent," it captures the essence of individuals who tend to avoid conversation or who are reserved in their speech. This term is often used to describe someone who may not express their thoughts and feelings openly, making them appear distant or unfriendly, although that's not necessarily the case.

In contrast, the other options provided do not align with the meaning of someone who is quiet or reserved. "Servile" (B) refers to a person who is excessively obedient or subservient, often in an obsequious manner. "Unequivocal" (C) means clear and unambiguous, and does not pertain to a person's level of speech. Lastly, "synoptic" (D) relates to summarizing or providing a general overview, nothing to do with a person's communication style. Thus, "taciturn" is the most accurate descriptor for a person characterized by habitual silence or limited speech.