This is the 11829th most frequent Polish word.
kończą
"Kończą" means "they finish" or "they are finishing."
In this sentence, 'kończą' is used as the third person plural present tense form of the verb 'kończyć,' which means 'to finish,' indicating that a group is finishing their work.
Kończą pracę na dziś.
They finish the work for today.
Here, 'kończą' is used reflexively as part of the phrase 'kończą się,' meaning 'are coming to an end,' referring to the conclusion of the summer holidays.
Kończą się wakacje.
The summer holidays are coming to an end.
The word 'kończą' in this context again denotes the action of finishing in the third person plural present tense, specifically the act of completing the construction of a new house.