Sleeper
Sleeper noun - One who sleeps.
Show all Definitions
Synonyms for Sleeper
Undercover and sleeper are semantically related. In some cases you can use "Undercover" instead a noun "Sleeper".
Undercover
Undercover noun - A person who tries secretly to obtain information for one country in the territory of another usually unfriendly country.
Usage example: within the city was a well-organized fifth column, and these undercovers would make themselves known as soon as the invading forces breached the city limits
Sleeper and undercover are semantically related. Sometimes you can use "Sleeper" instead a noun "Undercover".
Both words in one sentence
-
Carole, a North Korean sleeper agent in Geneva, ended up having a child whilst undercover.
Source: Series / Strike Back -
Sleeper is about an undercover secret intelligence agent working to bring down a massive super villain cartel — unfortunately, the bad life seems to agree with him...
Source: Going Native - In Chuck, the episode "Chuck Versus The Suburbs" shows Chuck and Sarah going undercover in a sunny suburban neighborhood to find a sleeper cell.
Source: Deep Cover Agent
Cite this Source
Undercover and Sleeper. (2016). Retrieved 2026, July 22, from https://thesaurus.plus/related/sleeper/undercover
Sleeper & Undercover. N.p., 2016. Web. 22 Jul. 2026. <https://thesaurus.plus/related/sleeper/undercover>.
Undercover or Sleeper. 2016. Accessed July 22, 2026. https://thesaurus.plus/related/sleeper/undercover.
Google Ngram Viewer shows how "sleeper" and "undercover" have occurred on timeline