Quick answer
A prefix does two things at once: it changes the meaning and it usually makes the verb perfective. писа́ть → написа́ть, переписа́ть, подписа́ть, вы́писать, запи́сать.
One verb, nine meanings
| Prefix | With писа́ть | Meaning |
|---|---|---|
| на- | написа́ть | to write (completed) |
| пере- | переписа́ть | to rewrite, to copy out |
| под- | подписа́ть | to sign |
| вы- | вы́писать | to write out, to prescribe |
| за- | записа́ть | to note down, to record |
| до- | дописа́ть | to finish writing |
| о- | описа́ть | to describe |
| при- | приписа́ть | to add in writing, to ascribe |
| рас- | расписа́ться | to sign off; to get married at the registry |
The same prefixes carry roughly the same meanings on other verbs, which is why they are worth learning as a set rather than word by word.
The core meanings
на- completion or “onto”. пере- across, again, re-. под- under, up to, slightly. вы- out of. за- start, or behind. до- up to a point, finishing. при- arrival, adding. у- away. о-/об- around, all over. раз-/рас- apart, in all directions.
A prefixed verb needs a new imperfective
Adding a prefix makes a verb perfective, so Russian builds a fresh imperfective from it, usually with -ыва-/-ива-: подписа́ть → подпи́сывать, записа́ть → запи́сывать, переписа́ть → перепи́сывать. That is how a single root ends up with dozens of forms.
Guess, then check
Prefix meanings are reliable enough to guess with — but not always literal. Расписа́ться really does mean both “to sign” and “to get married at the registry office”. Guess first, then confirm in a dictionary.
Typical mistakes
Я бу́ду написа́ть.
Я напишу́. / Я бу́ду писа́ть.
A prefixed verb is perfective, so it has no бу́ду future.
подписа́ть на газе́ту
подписа́ться на газе́ту
Subscribing takes the reflexive form.
Check yourself
What does записа́ть mean?