# nefarious

/nəˈfɛɹiəs/ (US) · /nəfˈeəɹɪəs/ (UK) · CEFR C1 · Adjective

Source: https://englishreference.com/word/nefarious
Updated: 2026-05-18

## Definition

describing something that is very bad, dishonest, or illegal. You use this to talk about activities that people do to hurt others or break the law.

For teachers: describing actions or intentions that are wicked, dishonest, or illegal. Often used to describe organized crime or secret plots.

## Examples

- The group was involved in nefarious activities.
- The detective spent months investigating the nefarious dealings of the local gang.
- The novel explores the nefarious influence of corporate lobbying on the democratic process, suggesting that the pursuit of profit often overrides the public good.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.