undercover man

noun

: one who undertakes to secure evidence of criminal or illegal actions by working with or among those who are under suspicion

also : one who secures a position (as in a business or factory) for the purpose of illicitly obtaining confidential information

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now