It is Buchanania lanzan as mentioned by Tabish. Nothopegia will have tetramerous flowers - 4 calyx lobes and 4 stamens. B. cochinchinensis (Syn. B. lanzan) mostly shows pentamerous flowers- 5 petals and 10 stamens - clearly seen in both the photographs (provided by you as well as Dinesh) .
Dr. Swapna Prabhu
Systematic Botanist/ Taxonomist
Bombay Natural History Society
Hornbil House, Shahid Bhagat Singh Marg
Dr. Salim Ali Chawk
Mumbai - 400 001.