Learner's definition of FRICTION
[noncount]
1
a : the act of rubbing one thing against another摩擦 b : the force that causes a moving object to slow down when it is touching another object摩擦力 2
: disagreement or tension between people or groups of people不和；分歧 — frictional
/ˈfrɪkʃənl̟/ adjective, technical — frictionless
/ˈfrɪkʃənləs/ adjective