Noun
sky; the air; the heavens
ワシが空を飛んでいる。An eagle is flying in the sky. weather
far-off place; distant place
state of mind; feeling
often as 〜空もない
(from) memory; (by) heart
usu. as 空で
falsehood; lie
Noun, used as a prefix
somehow; vaguely
before an adjective
fake
before a noun or a verb
Also written 虚【そら】