Well, why not just look it up?
thug [ THəg ]
NOUN
- a violent person, especially a criminal.
synonyms: ruffian · hooligan · vandal · hoodlum · gangster · villain · criminal · More
- a member of a religious organization of robbers and assassins in India. Devotees of the goddess Kali, the Thugs waylaid and strangled their victims, usually travelers, in a ritually prescribed manner. They were suppressed by the British in the 1830s.