1. to control or limit the expression of excitement, eagerness, or passionate interest in something
She had to restrain her enthusiasm when she heard the news about the promotion.
Ela teve que conter seu entusiasmo quando soube da notícia sobre a promoção.
2. to exercise self-control in showing one's excitement or eagerness
He restrained his enthusiasm to appear professional during the meeting.
Ele conteve seu entusiasmo para parecer profissional durante a reunião.