The word davai in Russian comes from the verb дава́ть (to give).
Davai literally means give, but the Russians use this word in many other situations where it has different meanings.
The most common translation of davai is come on. For example:
– Дава́й, пошли́!
Come on, let’s go!
When you hear davai davai!, it’s a common way to say come on, come on! or do it, do it!.
In other cases davai can mean let’s (do). You can learn more about it here: Russian imperative.
When you address a few people at once or talk in formal tone, davai becomes davaite. You can see the examples of it below.