One of the main drawbacks of the program is the amount of memory required.

drawback 是由动词 draw（拉、拖）和名词 back（后面）组成的复合名词，字面意思是"向后拉"，引申为"阻碍、缺点"。drawbacks 是 drawback 的复数形式，指"缺点、不利因素"。