The story goes back to the British Raj. There is a village in Gujarat by this name. Any person hailing from this village was called "Bhosadi ke", meaning belonging to Bhosadi.However, the meaning changed and is now considered extremely offensive.
The word may be considered equivalent of 'Motherfucker'
Bho - Sadi. The word is derived from two very distinct Hindi words, Bhoo and Sadi respectively. Bhoo meaning, our fertile earth which is compared to the fertile part of the human body namely the productive organs and Sadi meaning Rotten. The meaning reflects a negative meaning about an infertile human being. Therefore, concluding the compilation of the word Bhosadi. Although some people belive its roots to be in the historic village in Gujrat namely Bhosadi, it is truly out of perspective to talk of such a place in such a irrrespective manner.