“Wa-, dekkai fune da na-（わー、でっかい船だなー）”
“Nani ano dekai taido（なにあのデカい態度）”
“Cho dkkai oshiro!（超デカいお城!）”
The adjective “dekai（でかい：デカい）” is often used in casual Japanese conversation. If it’s a casual conversation, it can also be used at work.
Let’s see what “dekai” means, what examples it has, and what words to use if it’s not casual.
What is the meaning of “dekai” in Japanese?
“Dekai” means that its size is large.
If you start learning Japanese, you will first be taught that the word equivalent to “big” is “ookii（おおきい：大きい）”.
In Japan, the word “ookii” is used on a daily basis, but in casual conversation, the word “dekai” is also used.
The meanings of the above example sentences are as follows:
Wow, it is huge!
“Wa-, dekkai fune da na-
Wow, it’s a huge ship.
Nani ano dekai taido!?
What is that arrogant attitude!?
Cho dekkai oshiro!
What a huge castle!
However, there is an impression that “dekai” is a word that is generally used mainly by men.
Young women sometimes use the word in casual situations. Even adult women sometimes use “dekai”, but after all, it is only for casual situations. Adult women do not necessarily say “dekai” just because they have a casual conversation. Many women don’t use the word at all.
Even adult women who use “dekai” understand the situation and naturally switch between “dekai” and “ookii” properly.
In addition, “dekai” changes as follows.
All of these are casual and slang speaking styles.
All of the examples below mean “that alien is big”.
Ano eirian, deka!
Ano eirian, dekkai.
Ano eirian deke-.
Ano eirian dekke-.
You can also emphasize “dekai” further.
In that case, the prefix “do（ど）” that emphasizes nouns and adjectives is added to the beginning of this word and used as “dodekai（どでかい：どデカい）.”
a huge ship
a huge cake
a huge field
However, “dekai” was originally a combination of the two words “do” and “ikai（いかい）” which means “big” and “extreme”.
“Do” + “ikai” became the word “dekai”.
In other words, since “do” is already in “dekai”, there are two “do” in “dodekai”.
Well, anyway, the word “dekai” has already settled down as one of Japanese words, and the Japanese today use “dodekai” without thinking deeply about that.
Also, “dekai” originally meant huge and super-large, but over time it has come to be used in a similar sense to “ookii.”