without any friction (= the force that makes it difficult for an object to slide across or move through something)

Cartilage covers the ends of the bones in our joints and permits nearly frictionless movement. 软骨覆盖了我们关节的骨头末端，使得我们能够进行几乎无摩擦的运动。

a design for a frictionless bicycle 无摩擦自行车的设计

happening very easily without anything to make it slower or more difficult

We need completely frictionless trade, without tariffs or border checks. 我们需要完全无障碍贸易，没有关税，也没有边境检查。

The application offers frictionless downloading and sharing. 该应用程序提供无障碍下载和共享。