Definition of ガチ (gachi)
ガチ (がち, gachi) is a Japanese slang term that means “(something/someone is) so serious or real”. It is often used when you want to emphasise that there are no jokes or exaggeration at all in their statements.
1. Usage as an Adverb
Usually, ガチ is used as an adverb “ガチで”, e.g. “ガチでうまい” meaning “seriously tasty” and “ガチで勉強する” meaning “study seriously”. In particular, “ガチでやばい” is a very common phrase that means someone/something is so bad (or good, sometimes). For example, it is often used to describe a catastrophic typhoon, or someone who is so weird, abnormal and scary.
2. Usage as an Adjective
ガチ is also used as an adjective “ガチの” or “ガチな” to indicate that something is so serious, real, and/or important. For instance, “ガチの天才” means “bona fide genius” and “ガチな試合” means “serious match”.
Definition of マジ
マジ is probably the most common slang word in Japanese. It is basically a casual word for “とても (very)”, and is usually used as “マジ” or “マジで” before an adjective. For example, “マジ(で)うまい” means “so tasty” and “マジ(で)疲れた” means “(I’m) so tired”. As in ガチ, マジ is often combined with やばい to describe something bad or good. In a casual conversation, マジ is also frequently used as a short response to describe one’s surprise, like “Really?” in English.
Differences between ガチ and マジ
Although ガチ and マジ have very similar tones and meanings, there are some differences. First of all, ガチ contains a younger and more casual tone than マジ; therefore, if you are in your 30s or older, it’s probably better to avoid using ガチ (マジ also sounds young, but it is used among wider generations). Second, マジ is much more frequently used than ガチ (regardless of age), and therefore when people use ガチ instead of マジ, it sounds a bit more serious, e.g. ガチでやばい台風 (seriously dangerous typhoon) sounds a bit more dangerous and serious than “マジでやばい台風” (so dangerous typhoon).
Related Word: ガチ勢 (がちぜい, gachi zei)
ガチ勢 (gachi zei) is an internet slang term that describes people who are very serious about something. It is often used to describe gamers, but can be used for anyone who is adept at and serious about something. Sometimes, it contains a negative connotation like “too serious”, as shown in Ex4.
A: I’ve lost one million yen though an online fraud
B: What? Isn’t it seriously a big deal?
I saw a serious cosplayer in the train.
I had a match of Super Smash Bros. with its gachizei (expert) and got thrashed.
We were playing football for fun, but after gachizei joined us, it became boring.
(Here, gachizei indicates people who are always serious about playing football) )