空空

empty / vacuous / nothing / vacant / in vain / all for nothing / air-to-air (missile)

empty / air / sky / in vain

to empty / vacant / unoccupied / space / leisure / free time

empty-handed (idiom); fig. not receiving anything

as empty as anything (idiom); completely bereft / to have nothing / vacuous / hollow / empty (argument, head etc)

absolutely empty (space) / complete vacuum

deserted

empty / hollow / lacking in substance

petty thief (lit. quick fingered and vanish) / empty-handed / having nothing

air-to-air missile