This is the 1st most frequent Serbian word.
и
"And."
In this sentence, 'и' is used as a conjunction meaning 'and', linking two actions.
Имао сам времена и отишао до продавнице.
I had time and went to the store.
'И' is used in an emphatic context, equivalent to 'even' in English, to stress the conditions under which the action took place.
И по киши сам ишао у парк.
Even in the rain, I went to the park.
Here, 'и' functions as a simple conjunction to connect the subjects in the sentence.