From Rap Dictionary
Someone who has gone through a lot of hardship in life and becomes a thug-- you don't have any money so you make money by any means necessary. Livin' life thug style -- Tupac (To live and die in L.A. ).
Thugees, originally, were a murderous Gang in India during the British Colonial period. They were associated with the worship of Kali, the Hindu goddess of Death. Thugees were the bad guys in the Indiana Jones movie "Temple of Doom". Sometime in the late eighties, a fashion for all things Asian emerged in the black-power circles, especially among Nation of Islam and its splinter groups. See Wu-Tang Clan.
Thugs were an answer to Gangstas. Gangstas, the argument went, came from Europe (the Italian Mafia). But Thugs came from Asia.