The spokesperson stonewalled all the reporters' questions and refused to reveal any details.

stonewalled 是动词 stonewall 的过去式。stonewall 由 stone（石头）和 wall（墙）组成，字面意思是"石墙"，引申为"像石墙一样顽固地阻挡或拒绝"，指"顽固地拒绝回答或合作"。