i've read plenty of descriptions, they are usually vague and sound very similar to anapanasati.
could someone please elaborate?
sorry if this is a very broad question as "vipassana" is an ambiguous term, but nonetheless, you see "vipassana meditation" as a phrase used all over the place, so whatever it means to you, if you understand it, please explain it.
Well, in modern English language Buddhist usage, the term in Pali "vipassana" largely refers to a couple of streams of modern Theravadin meditation that largely derive from some doctrinal explanations from Burma / Myanmar in the last century or so.
However, the term "vipassana" (in Pali), and "vipasyana" (in Skt), are not confined to Theravada, and have always had a strong usage in almost all forms of Buddhism. It's paired with "samatha", and the two are "yoked together" to form the basis of Buddhist meditation as a general whole. Usually samatha comes first.
Samatha, from the root "sam" (to pacify), means calming, pacification, stilling, etc. and is roughly equivalent to samadhi "concentration".
Vipasyana, from the root "pas" (to see), insight, special seeing, observation, etc. and is roughly equivalent to prajna "knowledge".
Now, because almost every Buddhist school indicates that some sort of wisdom or insight is needed to become liberated, they all have some equivalent of vipasyana. They may not use this term, however, but the meaning is a commonality.