Hebrew is a living language. It’s always creating or borrowing new words from other languages. Most of the slang used today originates from the Big Orange (תל־אביב – Tel Aviv) itself and spreads throughout Israel pretty fast.

There’s a word equivalent to “dude” or “girl”. For a guy, you’d use אורדון (ur-dun) and for a girl you have אורדונית (ur-dun-it).
הי אורדון, מה המצב? (hey ur-dun, ma ha-mats-av?) – Hey dude, what’s up?
הי אורדונית, מה המצב? (hey ur-dun-it, ma ha-mats-av?) – Hey girl, what’s up?

פּיגוז (pi-guz) – very nice, very good, ‘da bomb’
הכל טוסט (ha-kol tost) – Everything is toast (everything is okay)
לחיות בסרט (lichyot beseret) – to live in a movie (said about a person who is vaguely connected to reality)
להתקטן (le-hit-ka-ten) – to be petty
סתאאאאאאאאאאאם (staaaaaaam) – I’m just joking.

From English

Slang that originated from English actually comes from the time when Israel was British occupied territory (The British Mandate). Some of these include:
פּנצ׳ר (pan-cher) – a flat tire (‘puncture’)
פּעם שלישית גלידה (pa-'am slishit glida) – A third time ice cream
תקנה לי גלידה (tikne li glida) – Buy me an ice cream

These last two phrases are used if you see someone three times in a row in a short period of time (even the same day). Why? It’s a corruption of the English “If I see you a third time, I’ll scream”

Is it okay? – שַׁיָיךְ

Pronounced “sha-yakh” This slang term is used primarily among the ultra orthodox and very religious Jews. The idea behind this word means something is under the ownership of someone. It’s slang meaning, however, expresses the question if something is correct, suitable, relevant, etc. Similar to saying something like “Does it bother you if…” or “Is it okay…?”

It’s not שַׁיָיךְ to dress this way in the synagogue.
What type of gift is שַׁיָיךְ for Bar Mitzvah?
Is it שַׁיָיךְ to go shopping during Sabbath?*

*no, it’s not שַׁיָיךְ