This is the 538th most frequent Icelandic word.
leiknum
The Icelandic word "leiknum" is the dative singular form of "leikni," meaning "skill" or "proficiency" in English.
The word 'leiknum' is used here as the definite dative singular form of 'leikur', meaning 'the game'.
Þátttakendur í leiknum hlóu mikið.
The participants in the game laughed a lot.
Here, 'leiknum' is in the definite dative singular form, referring to a specific game where progress was achieved.
Hann bætti sig stórlega í leiknum.
He greatly improved in the game.
In this context, 'leiknum' denotes enjoyment related to participation in the specific game, using the dative case.