something empty / ineffectual / false

by heart, from memory, by rote

empty; vain; sky

pretty, gorgeous, beautiful / clear, clean, pure / clean, not dirty / tidy, neat, everything put away / fair, impartial, of clear conscience

lip service; promising but empty talk / skillful completion of a task

a black-backed wagtail (Motacilla alba lugens)

pretty, beautiful

Kyūjitai form of 空気: air, atmosphere; atmosphere, mood

empty box

high in the sky