david waker 
Explained: How supari became an underworld code word
According to retired Mumbai Police ACP Vasant Dhoble, who joined the force in the mid 70s, the connotation comes from a tradition in rural Maharashtra of inviting guests to a wedding with a paan and supari. Subsequently, paan-supari was given to signal commitment to a deal or contract — such as one to build or repair a house. The recipient of such a contract might say, “kamachi supari aali ahey (we have got the contract for the work)”.
The majority of those who joined the police came from rural Maharashtra, and they brought their language and expressions with them, Dhoble said. At some point, as activities of the Mumbai underworld came to dominate crime in the city and gangland killings became commonplace, the expression ‘uska supari isne diya’ came to be understood as giving the contract for a murder to a mercenary or hitman.
In his book ‘Dongri to Dubai: Six Decades of the Mumbai Mafia’, journalist-author S Hussain Zaidi traced the origin of supari to an interesting ritual said to have been followed by Bhim, chief of the Mahemi tribe and overlord of Mahim. According to Zaidi, whenever Bhim had to assign a difficult task, he would call a meeting of his warriors at Mahim fort where, after a sumptuous feast, a plate with a betel leaf would be brought in and placed in the middle of the gathering. The man who picked the leaf was entrusted with the difficult task.
