This is the 607th most frequent Icelandic word.
feyki
The Icelandic word "feyki" means "extremely" or "very."
Here, 'feyki' is used as an adverb to emphasize the extent of the goodness of the weather.
Það var feyki gott veður í dag.
It was incredibly good weather today.
In this sentence, 'feyki' acts as an intensifier for the adjective 'clever' to signify a high degree of cleverness.
Hún er feyki gáfuð í leikjum.
She is remarkably clever in games.
'Feyki' modifies the adverb 'quickly,' indicating an exceptional speed.