Its a curse word. It is of level comparable to calling someone's momma your fiancee and so should not be called to just anyone but to only those who really piss you off and you wanna piss them off really bad. Senthilnathan's are ALWAYS lustful, selfish, SADIST and a pain in the ass of the society.
I give you the curse of being a mf-ing Senthilnathan.