The word umbrella is derived from the Latin word umbra meaning shade or shadow. Umbrellas have been used in many shady dealings over the years:

The story of an umbrella developed by the KGB here

An umbrella developed for self defense here 

In 1901, two women attacked a policeman during a cigar factory strike on NY’s Canal Street. The girls struck an officer Flynn on the head with umbrellas repeatedly, and pulled on his coat tails until the jacket gave way and was ripped from his back. Luckily, no one was seriously hurt during the incident.

Fact Credit: Wikipedia; New York Times

Image Credit: OAK