unsub
n.— «Unsub is shorthand for “unknown subject,” meaning the person believed to have committed the crimes. Nor is it new. There was a 1989 series called Unsub, which followed a government unit investigating serial killers.» —“‘Unsub’ unmasked and other TV queries” by R.D. Heldenfels Akron Beacon Journal (Ohio) Apr. 6, 2006. (source: Double-Tongued Dictionary)
Further reading
An anadrome is a word that forms a whole new word when you spell it backwards. For example, the word “stressed” spelled backwards is “desserts.” Some people’s first names are anadromes. There’s the girl named Noel...
For rock climbers, skiers, and other outdoor enthusiasts, the word send has taken on a whole new meaning. You might cheer on a fellow snowboarder with Send it, bro! — and being sendy is a really great thing. Plus: a nostalgic trip to Willa...