reticent
adjective
UK/ˈret.ɪ.sᵊnt/
US/ˈret̬.ə.sᵊnt/
Definitions of reticent adjective
Characterized by a disinclination to speak freely about one's thoughts or feelings; reserved.
He always remains reticent about his personal life.
She was quite reticent about her past experiences.
During the meeting, he was reticent about the details of the proposal.