頭でっかち

Meanings

1. Na-adjective, No-adjective, Noun

   top-heavy
2. big-headed
3. overly-theoretical

• 彼かれは頭あたまでっかちだ。

  He is an armchair theorist.

• うちの会社かいしゃは頭あたまでっかちだ。

  Our company is too top-heavy.

• 頭あたまでっかちの人ひとね、ちょっぴりめんどくさそうだけど別べつに嫌きらいじゃないよ。

  I find overthinkers to be a little hard to deal with but I don't hate them so to say.