The term, vipassana ‘insight’, is a noun form. It combines two elements, vi and the verbal form, passati, in the sense that ‘seeing completely and perfectly’, phenomena as they really are. For the practical meaning of vipassana, you need to look at the verbal form, passati, in the suttas (particularly in SN/SA suttas). Note: passati is always come together with another verb, jaanaati.
Thus, samatha and vipassana are not the same practice.