Lira
It often means "to play", i.e., to play a sport or a musical instrument. "Jag lirar ofta gitarr" translates to: I often play the guitar.
Dyka upp
When someone asks "when are you going to 'dyka upp'", it means when are you going to arrive at a certain place. "Jag kommer att dyka upp runt 17:00 hemma hos dig" translates to: I'll arrive around 5:00 PM at your place.
Fett
Used by younger people. "Det rockar fett" means something is great.
Chilla
Also commonly used by younger people. "Ska vi chilla" means let's take it easy and relax. "Ska vi chilla hos mig" means: let's take it easy and hang out at my place.
Pjäs
"Pjäs" can mean a play, but it can also be used to describe something impressive. "Vad är det för en pjäs?" means: what is that thing (something big and impressive)?
Banga(r)
To "banga" means to skip or not show up. "Jag bangar nog festen" means I'm skipping the party and not showing up.
Shit
"Shit" is used as an expression of surprise, similar to the English word "shit". "Shit vad är det där för något" means: wow, what is that thing?
Steka
"Steka" means to abandon or give up on something. "Vi steker den idén" means we're abandoning that idea.
Hooka
To "hooka" means to meet up, similar to the English phrase "hook up". "Ska vi hooka upp efter jobbet" means shall we meet up after work?
Schysst
"Schysst" means something is nice, fair, or cool. "Vad schysst av dig att bjuda på glass" means: that's really nice of you to offer ice cream.
Now you've got some common expressions that'll help you keep up when someone's chatting with you informally in Swedish.
