Hm, when I look it up, I see the translation given as “It’s fucking hot.” — wonder if Clozemaster could be doing some internal bleeping here.
“It’s fucking hot.” seems like a pretty accurate translation.
In general, zajebisty is used as a vulgar adjective with positive connotations. So if something is zajebisty, it’s “awesome” or rather “freaking awesome”.
When used as an adverb (zajebiście – as it is used here), it means just “very very very”, or “freaking”, or “fucking”, depending on the context. In this case, it’s not necessarily positive—the ultimate meaning will depend on the adjective that is being emphasized by this adverb.
Zajebisty and zajebiście are generally considered swear words, though they aren’t so bad as far as profanities go. In recent years, it’s got to the point where it’s not so shocking (for most people) when someone uses this word on breakfast television, especially if they’re really excited about something.