Meanings

vacant and unthinking

fictitious transaction

underground space

New Tokyo International Airport Authority

arching backward

unable to read the situation

karate gi

to have a good opportunity only to let it slip from your grasp

address space

air guitar

earth, water, fire, wind and void (the five elements)

blank email (e.g. for signing up to an email list)

Great Interregnum (period of the Holy Roman Empire; approx. 1254-1273)

perfect vacuum

air tank (scuba)

air sac

one-way airline ticket

to be away from home

air-fuel ratio

hyperspace