This is the 45th most frequent Icelandic word.
mjög
"Very."
Here, 'mjög' is used to intensify the adjective 'hamingjusöm' (happy), emphasizing the extent of happiness.
Ég er mjög hamingjusöm í dag.
I am very happy today.
In this sentence, 'mjög' serves to highlight the significance of the adjective 'mikilvægt' (important).
Þetta verkefni er mjög mikilvægt.
This task is very important.
'Mjög' is applied here to strengthen the descriptive adjectives 'stórt' (big) and potentially 'fallegt' (beautiful), underlining their quality.