noun, noun which may take the genitive case particle 'no'
Used as a noun or の-adjective for a container, space, schedule slot, glass, wallet, etc. having nothing inside or no content.
この箱は空だ。
This box is empty.
空のグラスを下げてください。
Please clear away the empty glasses.
prefix
unloaded; unburdened; empty-handed
Prefix use in compounds such as 空荷 and 空身, indicating that someone or something is carrying no load, baggage, or equipment. Everyday 'empty-handed' is often expressed with 手ぶら.
荷物を降ろしたトラックは空荷で戻った。
After unloading, the truck returned empty.
prefix
empty; false; insincere; no-show
Prefix use in fixed or semi-fixed compounds where something exists in name only or lacks sincerity, substance, or follow-through: 空手形 can mean an empty promise or dishonoured bill, 空元気 is forced cheerfulness, カラ予約 is a fake or no-show reservation, and 空世辞 is empty flattery.
あの支援策は、実行されずに空手形に終わった。
That support measure ended up being an empty promise and was never carried out.
疲れているのに、彼は空元気を出していた。
Even though he was tired, he was putting on a cheerful front.
カラ予約を防ぐため、店は予約時にカード情報を求めている。
To prevent no-show reservations, the restaurant asks for card information when customers book.