Bad Word Filter - Profanity Detector & Text Cleaner
Free online bad word filter to detect, highlight, and remove profanity from text. Supports leetspeak detection, severity levels, and custom word lists.
Custom Word Lists
About
Content moderation failures cost platforms users, advertisers, and legal standing. Manual review does not scale. A single missed slur in user-generated content can trigger regulatory action under frameworks like the EU Digital Services Act or COPPA. This tool scans input text against a multi-category profanity dictionary of over 300 terms, applies leetspeak normalization (mapping characters like @ → a, 0 → o, $ → s), and classifies each match by severity: Mild, Moderate, or Severe. A built-in whitelist reduces false positives on legitimate words containing partial matches. The tool approximates production-grade filtering but cannot replace contextual NLP analysis for sarcasm, coded language, or novel slang.
Formulas
Each detected word receives a weighted severity score. The overall text toxicity index T is computed as:
Where wi is the severity weight of the i-th flagged word: Mild = 1, Moderate = 3, Severe = 5. W is the total word count of the input text. n is the number of flagged words. A score of T < 1 indicates clean content. T ≥ 5 indicates high toxicity.
Leetspeak normalization applies a character mapping function m(c) before pattern matching:
Reference Data
| Category | Severity | Approx. Count | Common Obfuscation | False Positive Risk |
|---|---|---|---|---|
| General Profanity | Moderate - Severe | 45 | Vowel substitution, asterisks | Low |
| Slurs (Racial) | Severe | 35 | Leetspeak, spacing | Medium |
| Slurs (Gender/Sexual) | Severe | 30 | Abbreviations, phonetic | Medium |
| Sexual Content | Moderate - Severe | 50 | Emoji substitution, acronyms | High |
| Violence / Threats | Severe | 25 | Misspelling, coded language | Medium |
| Drug References | Mild - Moderate | 20 | Slang evolution | High |
| Insults (Mild) | Mild | 40 | Rare | Low |
| Scatological | Mild - Moderate | 20 | Vowel removal | Low |
| Religious Profanity | Mild | 15 | Euphemisms | Medium |
| Homophobic Slurs | Severe | 20 | Abbreviation, leetspeak | Medium |
| Body Shaming | Moderate | 15 | Rare | High |
| Ableist Slurs | Moderate - Severe | 15 | Abbreviation | High |