immature / juvenile / childish / immature person / juvenile person / childish person / amateurish / inexperienced / unprofessional

七七日: the forty-ninth day after a person dies; the Buddhist memorial service that occurs forty-nine days after a person dies

Clipping of 特殊相対性理論 (tokushu sōtaisei riron, “special relativity”).

fantasia (music)

grassland, prairie, savanna / (Internet slang) LOL, LMAO; used to indicate amusement or laughter

fantastic, illusory, imaginary

(education, school subject) Short for 現代社会 (gendai shakai, “modern society”).

(idiomatic) to be infatuated (with); to be hooked (on); to lose one's heart (on); to be engrossed

Short for 現代パロディ (gendai parodi).

(education, school subject) Short for 現代国語 (gendai kokugo, “Japanese”)