Diffident
Part of speech: adjective
Definition: Lacking confidence in others; distrustful. Lacking confidence in one's self; distrustful of one's own powers; not self-reliant; timid; modest; bashful; characterized by modest reserve.
Reserved
Part of speech: verb
Definition: To keep back; to retain.
Part of speech: adjective
Definition: Slow to reveal emotion or opinions.Set aside for the use of a particular person or party.
Example sentence: We must distinguish between speaking to deceive and being silent to be reserved.