This is the 714th most frequent Swedish word.
fin
"Fin" in Swedish means "fine" or "nice" in English.
Here, 'fin' is used as an adjective that describes the quality or attractiveness of the dress, meaning 'beautiful' or 'fine'.
Du har en mycket fin klänning på dig idag.
You are wearing a very beautiful dress today.
In this sentence, 'fin' is used to describe the day in a general positive sense, implying it is suitable or pleasant.
Det var en fin dag för en promenad i parken.
It was a nice day for a walk in the park.
Here, 'fin' is used metaphorically to describe the delicacy or skillfulness of handling the brush.