Racism is the belief that inherent different traits in human racial groups justify discrimination. In the modern English language, the term "racism" is used predominantly as a pejorative

Pejorative

Pejoratives , including name slurs, are words or grammatical forms that connote negativity and express contempt or distaste. A term can be regarded as pejorative in some social groups but not in others, e.g., hacker is a term used for computer criminals as well as quick and clever computer experts...

 epithet

Epithet

An epithet or byname is a descriptive term accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, divinities, objects, and binomial nomenclature. It is also a descriptive title...

. It is applied especially to the practice or advocacy of racial discrimination of a pernicious nature (i.e. which harms particular groups of people), and which is often justified by recourse to racial stereotyping or pseudo-science.

Modern usage often equates "racism" and "racial discrimination" and defines the latter term only as applying to pernicious practices.