A masterless samurai. Samurai typically became ronin if the guy they were a retainer to got killed off in a losing battle. It wasn't a good spot to be in, even if it has become romanticized. A ronin didn't get his ration of rice from his master to support his household, but as a samurai he couldn't take a mundane job either.

A ronin is a samurai who does not serve any master. It can be by choice or due to circumstances. Some samurai rather than spend their lives serving a lord prefer to study and improve their skill (usually with swords, but not always). Some become masterless due to being on the losing side of a war or if the master they serve either fell in disgrace whereby the clan is usually dissolved (everybody loses their job is not their lives). In some cases, a ronin may actually be a samurai employed by a lord to act as a spy.

A ronin was a samurai (elite Japanese warrior) under no lord during the feudal period (between 12th–19th century) of Japan.

Ancient term used for a loner Samurai who did not belong to any shogun or noble family and was primarily a hired sword.

The actual term means "wave-man".... A man adrift on the waves of life.

What michinoku2001 and Georgie said in a nutshell. For more info look them up!

http://en.wikipedia.org/wiki/Rōnin

Unemployed military doing security and other odd jobs.