Dictionary: “空”

sky;air;mid-air

empty nest

empty can

air transport;air lift;airlift

empty seat;unoccupied seat

space;room;airspace

air;atmosphere

emptiness;hollowness;vacancy;void

racing (of an engine);idling

daydream;fantasy;fancy;vision

empty;vacant;hollow

blank column;blank space

empty stomach;hunger

vacant land;unoccupied ground;empty lot

air-raid

aircraft carrier

vacant house;unoccupied house

karate

empty conveyance;empty taxi;free taxi

aerial bombing

unprecedented;record-breaking

cavity;hollow;cave;cavern

airport

air force

air route;air lane

space;room;gap;emptiness

air conditioning

swing and a miss

airspace

empty (e.g. argument);insubstantial;hollow;fruitless

empty gun;gun loaded with blanks;firing a blank

blank space (in a document)

not carrying anything;unburdened;empty-handed

by air;by plane

mood;situation

(punching and) failing to make contact

having spaces available (of a parking lot)

empty point

blank;void;gap;vacuum

inanity;pointlessness;meaninglessness

vacancy;vacant post

going in circles (of an argument, discussion, etc.);spinning one's wheels;going nowhere

empty house;empty home

hollow

being empty-handed;having nothing in one's hands

vacancy;opening;empty seat

dishonoured (bill, promise, etc.);false;no-show (reservation);put-on (cheeriness, courage, etc.);empty (compliments);insincere

free time;time to spare

someone with no presence;someone who doesn't stand out at all