Undercover works refer to activities that involve secret investigations, surveillance, or intelligence gathering. Synonyms for this term may include covert operations, clandestine operations, hidden operations, stealth operations, or undercover operations. These words often connote a sense of secrecy and concealment, implying that the activities being undertaken are meant to remain hidden from public view. Other synonyms for undercover works could include spy work, undercover investigation, intelligence gathering, or stealthy surveillance. Regardless of the term used, these activities are often carried out by law enforcement agencies, private investigative firms, or intelligence services to uncover criminal activity or gather information in a discreet manner.