【はまる・はまって(い)る・hamaru・hamatte(i)ru】hooked/crazy about

はまる/はまってる・hamaru/hamatteru = hooked/crazy about/

You can use this to say:

I'm hooked on this game.
He is crazy about Ramen.
I'm obsessed with Korean drama.

"Hamaru" originally means "to fit into something" or "stuck in something". These meanings are still intact, but nowadays, "Hamaru" is used very often to express "being hooked on/crazy about something". ("Obsessed" maybe, but that is a bit too intense.)

"Hamaru" used in this way is a slang. It is widely accepted and used throughout the society, but still, it might be a fad. Using it in a casual conversation is fine, but it's safe not to use it in an official setting.

Most often, you use this to say you are hooked on something, "xxxx ni hamatteru/hamattemasu."

EXAMPLES

Hooked on

いま、このげーむに、はまってます。
(Ima, kono gēmu ni hamatte masu.

(I'm hooked on this game now.)

そうなの？そんなにおもしろいの？
(sōnano? sonnani omosiroi no?)

(You are? Is it that good?)

Crazy about

わたしのおとうとは、おわらいに はまってるんです。
(Watasi no otōto wa, owarai ni hamatte irundesu.)

(My little brother is crazy about "Owarai".)

うちの おにいちゃんもです！
(Uti no onīchan mo desu!)

(My big brother too!.)

"My" is usually translated to "Watasi no", but often, people use "Utino" when it belongs to their family or household, for example, "uti no reizōko (refrigerator)" instead of "watasino reizōko"

"Onīchan" is a casual way to call "big brother". In formal conversation, you use "Ani".

A tip

Before "Hamaru" got its popularity, words such as: