This is the 562nd most frequent Slovenian word.
dali
"Dali" in Slovenian means "they gave".
In this sentence, 'dali' is the past tense form of the verb 'dati' (to give or to place), indicating an action of having placed something somewhere.
Ali ste dali knjige na mizo?
Did you place the books on the table?
Here, 'dali' conveys the notion of giving one's best, again as a past tense form of 'dati'.
Mi smo dali vse od sebe za ta projekt.
We gave our all for this project.
In this usage, 'dali' expresses the action of giving something to someone, used in past tense.