These words are comparable in that they are all used when one wishes to describe the character, speech or actions of people who have in some way offended one’s sensibilities or moral standards. Vulgar and obscene are similar in their suggestion of indelicacy or indecency, but vulgar points more to a lack of refinement or good taste while obscene suggests a preoccupation with the pornographic: displaying shockingly vulgar table manners; a madman shouting obscene epithets.

Literally, coarse , crude and gross refer to physical properties and carry the idea of an absence of fineness or delicacy. Coarse suggests roughness: a coarse fabric. Crude points to rawness or a lack of preparation: crude oil. Gross is used in reference to excessive fat: gross features. In their figurative meanings, the words are applicable to persons and their behaviour. Coarse and crude are like vulgar in indicating a lack of refinement, as in manners or language: coarse behaviour that was a reflection of a complete absence of training in the rudiments of social conduct; a group of schoolboys making crude jokes about their teachers. Gross , with its connotation of excessive as applied to unacceptable behaviour, is the strongest of these three words, and suggests a reversion to animal instincts: the gross behaviour of an invading army.