Quote Originally Posted by xXHoax View Post
About 99.97% of Russian verbs have an Imperfective-Perfective pair

Most often, one verb will be imperfective, and the perfective will be the same root with an added prefix. по- being the most common
Here with пить you can see that the prefix вы- is what constitutes the perfective.

Sometimes an extra in-syllable is added to form imperfective from perfective -ыв-

A common hierarchy structure is:
ROOT [imperfective] -pair- prefix1-ROOT [perfective]
prefix2-ROO-infix-T -pair- prefix2-ROOT [perfective]
prefix3-ROO-infix-T -pair- prefix3-ROOT [perfective]
prefix4-ROO-infix-T -pair- prefix4-ROOT [perfective]
It’s even more complicated. There is the verb попи́ть, another perfective counterpart of the unprefixed пить.
Попи́ть means ‘drink some’ while вы́пить is ‘finish drinking’. Although, they are interchangeable in many cases.

Moreover, the verb вы́пить has its own prefixed imperfective form выпива́ть ‘drink (a certain amount)’.
E.g. «Я выпива́ю 5 ча́шек ко́фе в день» ‘I drink 5 cups of coffee a day’.

Another nuance is that the pair выпива́ть—вы́пить often means ‘drink alcohol’, especially without a direct object specified.
«Он ча́сто выпива́ет» ‘He drinks hard’
«Хо́чешь пить? — Нет, я хочу́ вы́пить» ‘Are you thirsty?’ ‘No, I wanna booze up’