Bandit

Not really a "profession" in the traditional sense however it is a form of "profiteering". 

Most bandits are forced into this lifestyle by circumstance. This profession has a short life expectancy, they often form together as groups to increase their success and survival rates, however such groups are often ruled by some brutal dictator.
A lot of bandits are desperate people and are easily manipulated into doing terrible acts by those that have the coin or know how.

Perception

Social Status

Bandits are feared and hated. They are actively hunted by lawmen and town guards.

Demographics

Thankfully only a low percentage of the population are bandits. After wars, disbanded armies and mercenary groups can cause dangerous groups of bandits to be formed.
Long periods of unemployment and hunger can also create bandit groups out of desperate citizens although less dangerous than disbanded armies they can still cause problems.