Frotter vs. frictionner
While both frotter and frictionner translate to to rub in English, they are used in different contexts. The word frotter is the general and most common term used for rubbing any surface, object, or body part. On the other hand, frictionner is much more specific and refers to briskly rubbing the skin or body, usually for therapeutic, athletic, or medical purposes.
Frotter
The verb frotter is the standard, everyday word for rubbing. It applies to a wide variety of situations, such as cleaning a surface, polishing an object, scratching an itch, or simply moving a hand or cloth back and forth over something.
Je dois frotter la tache avec du savon pour l'enlever.
(I have to rub the stain with soap to remove it.)
Il se frotte les yeux parce qu'il est très fatigué.
(He rubs his eyes because he is very tired.)
Le chat adore se frotter contre les meubles du salon.
(The cat loves to rub against the living room furniture.)
Elle frotte l'argenterie avec un chiffon sec pour la faire briller.
(She rubs the silverware with a dry cloth to make it shine.)
Frottez vos mains l'une contre l'autre pour vous réchauffer.
(Rub your hands together to warm yourself up.)
Ne frotte pas cette blessure car tu risques de l'aggraver.
(Do not rub that wound because you risk making it worse.)
Frictionner
The verb frictionner means to rub briskly or vigorously, and it is almost exclusively applied to the human body or skin. It is frequently used when applying ointments, oils, or lotions to stimulate blood flow, warm up muscles, or treat an illness.
Le médecin lui a dit de frictionner son dos avec cette pommade.
(The doctor told him to rub his back with this ointment.)
Il est conseillé de se frictionner vigoureusement avec une serviette après un bain glacé.
(It is advised to rub oneself briskly with a towel after an ice bath.)
Le sportif frictionne ses jambes avec de l'huile chauffante avant la course.
(The athlete rubs his legs with warming oil before the race.)
Quand j'étais malade, ma grand-mère me frictionnait la poitrine avec du baume.
(When I was sick, my grandmother would rub my chest with balm.)
Le coiffeur frictionne le cuir chevelu du client avec une lotion tonique.
(The hairdresser vigorously rubs the client's scalp with a tonic lotion.)
Summary
In short, choose frotter for almost all everyday situations involving rubbing, whether it is for cleaning objects, petting an animal, or wiping your eyes. Reserve frictionner for vigorous, health-related, or therapeutic rubbing of the skin, such as massaging muscles with oil, applying medicinal balms, or briskly drying off with a towel.