Dégoûtant vs. répugnant vs. dégueulasse

In the French language, various words exist to express the idea of something being unpleasant to the senses or morally offensive. 'Dégoûtant', 'répugnant', and 'dégueulasse' are three such words that convey different nuances of what English speakers might refer to as 'disgusting' or 'repulsive'. While they can often be used interchangeably, they carry slightly different connotations and are used in different contexts.

Dégoûtant

This word is a formal term that directly translates to 'disgusting'. It can relate to both physical revulsion and moral disapproval.
Les ordures dans la rue étaient dégoûtantes après la grève des éboueurs.
(The garbage on the street was disgusting after the garbage collectors' strike.)
L'attitude de cet homme envers les animaux est vraiment dégoûtante.
(That man's attitude towards animals is really disgusting.)

Répugnant

'Répugnant' carries a sense of deep disgust or repulsion, often in a moral or intellectual sense. It can be physical as well, but it is typically reserved for reactions to actions or behaviors.
Il trouve l'idée de tricher aux examens répugnante.
(He finds the idea of cheating on exams repulsive.)
Les images de violence à la télévision sont répugnantes et inacceptables pour les enfants.
(The images of violence on television are repulsive and unacceptable for children.)

Dégueulasse

Very colloquial in nature, 'dégueulasse' is an informal term similar to 'gross' or 'nasty'. It often refers to a visceral physical reaction, especially regarding taste, cleanliness, or hygiene.
Ce restaurant est dégueulasse; mon steak était cru!
(This restaurant is gross; my steak was raw!)
Ne touche pas à ça, c'est dégueulasse!
(Don't touch that, it's nasty!)

Summary

'Dégoûtant', 'répugnant', and 'dégueulasse' all serve to communicate different aspects of being off-putting. While 'dégoûtant' can be used broadly and formally for both physical disgust and moral disdain, 'répugnant' often implies a more profound sense of ethical or intellectual outrage. On another front, 'dégueulasse' delivers a stronger punch with its informal tone that vividly describes something as filthy or vile, particularly in contexts related to taste and sanitation.