Fetching details from the dictionary...

space; room; gap; emptiness
vacancy; opening; empty seat
free time; time to spare
disuse; unused thing
空きがあれば入りたい。
I'd like to get in if there's room.
このホテルには空きがないようです。
It seems there are no vacancies at this hotel.
今週末は空きがあるので遊びに来てね。
I have free time this weekend, so come visit.