Oxford University Press has developed two lists of offensive words and expressions, specifically developed for filter applications in the contexts of web pages and email.
Each list features a grading system describing vocabulary type and offensive strength for each term, plus collocational information to help identify the terms in context.

Coverage: 4500 words and expressions; 10-category classification system; UK and US usage covered, plus other world English
Features: graded by class (offensive/vulgar), and type (racist, sexist etc); rated by strength (high/moderate/mild); part of speech included; morphological status marked (standalone/fixed collocation etc); collocational information included; practical screening recommendation
Format: tab-delimited ASCII
File Size: 262kB