apologetic smile

Translations
извиняющаяся улыбка
She gave an apologetic smile when she bumped into him.
Она извиняющейся улыбнулась, когда столкнулась с ним.
Definitions
An apologetic smile is a facial expression that conveys regret or remorse, often characterized by a slight upward curve of the lips and sometimes accompanied by a lowering of the eyes or a sheepish demeanor. It is typically used in social situations to express an acknowledgment of a mistake or to soften the impact of an apology.