un·​sub ˈən-ˌsəb How to pronounce unsub (audio)
plural unsubs
US law enforcement, informal
: the unknown perpetrator of a crime
Not one but two murderous unsubs are on the loose in tonight's Criminal MindsTV Guide
Rhyme remembered the thousands of times he'd run crime scenes. Sometimes a miracle would happen. He'd be looking around and somehow ideas about the unsub would come to him. He couldn't explain how.Jeffery Deaver

Examples of unsub in a Sentence

Recent Examples on the Web The trauma of her shooting and the pressure of her job leads to the BAU agent shooting an unsub. Alamin Yohannes, EW.com, 10 June 2024 The 40-second clip depicted the BAU agents in a number of different scenarios and suggested Prentiss died after the events with the unsub Ian Doyle in season 6. Adrianna Freedman, Good Housekeeping, 1 Apr. 2023 The 10-episode series from original series writer and producer Erica Messer will have a COVID-19 pandemic twist this time around as the criminal profilers track down a new unsub, who has built a network of serial killers during quarantine. Jessica Wang, EW.com, 13 Sep. 2022 Debuting on September 22, Criminal Minds follows a group of criminal profilers who work for the FBI as members of its Behavioral Analysis Unit (BAU) using behavioral analysis and profiling to help investigate crimes and find the suspect known as the unsub (unknown subject). Marc Berman, Forbes, 15 July 2022 The real masterstroke is casting Zach Gilford as the prime unsub, the spiritual leader of a nationwide network of murderous acolytes. Joshua Alston, Variety, 21 Nov. 2022 Fairly quickly, the agents ruled out a foreign power as the culprit, deciding that the unsub must be a C.I.A. insider. Patrick Radden Keefe, The New Yorker, 6 June 2022

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'unsub.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


unknown (or unidentified) subject

First Known Use

1965, in the meaning defined above

Time Traveler
The first known use of unsub was in 1965

Dictionary Entries Near unsub

Cite this Entry

“Unsub.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/unsub. Accessed 14 Jul. 2024.

Last Updated: - Updated example sentences
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