Mais -> ms

= Mais
= But

"Je voudrais l'acheter ms j'ai plus de thunes"
= "I'd like to get it but I'm broke"

Comment -> cmt

= Comment
= How

"Je sais pas cmt il l'a fait"
= "I don't know how he did it"

Qu'est-ce qu'il y a -> ksk y a

= Qu'est-ce qu'il y a
= What's going on

"Ca va ? Ksk y a ?"
= "How are you? Is everything OK?"

Mort de rire -> mdr

= Mort De Rire
= LOL

"Finalement il était 2h en retard, mdr !"
= "In the end he was 2h late, lol!"

Flouze (m)

= Argent (m)
= Money
Synonyms: All the other words in the "Money" category


"Il me reste pas de flouze pour sortir les weekends"
= "I don't have enough money left to go out in the week ends"

Tune, thune (f)

= Argent (m)
= Money
NB: can be spelled with or without the "h"
Synonyms: All the other words in the "Money" category

"Il m'a prêté de la thune"
= "He lent me some money"

Mater

= Regarder
= To watch, to check out

"On a maté un film hier soir"
= "We watched a movie yesterday"

"Il aime mater les filles en été"
= "He likes to check out girls in the summer"

(There's a third meaning too, feel free to add examples of it in the comments!)