[verb] [T] -mm-To dam a river is to build a dam across it in order to store the water.They're going to dam (up) the river and build a reservoir. [T or M]If you dam up your feelings, esp. anger or sadness, you do not allow yourself to express or show your feelings in a healthy way.
DAM
Meaning of DAM in English
Cambridge English vocab. Кембриджский английский словарь. 2012