There are many different ways to express how awesome something is in Icelandic. Some of the more common ones are the subject of this magnificent post It ties in well with the topic of intensifiers, which was dealt with nicely in Colloquial Icelandic by Daisy Neijmann in Chapter 12 (Tómstundir), if you have a copy of that. Below are just the dictionary definitions; these words seem to be open to a great variety of translations though, so don’t be surprised to find even more meanings attributed to them.
glæsi·legur adj splendid, magnificent, elegant rosa·legur adj tremendous, fantastic æðis·legur adj fantastic, great, terrific gleði·legur adj delightful, pleasant dásam·legur adj wonderful, admirable, glorious yndis·legur adj wonderful, marvellous snilldar·legur adj masterly, brilliant gríðar·legur adj enormous
Hann er glæsilegur söngvari. – He is a magnificent singer.
Þetta var rosalegur dagur. – That was a fantastic day.
Þetta er æðisleg tilfinning. – That is a great feeling.
Gleðileg jól! – Merry Christmas!
Við borðuðum dásamlegan mat. – We ate wonderful food.
Sumarið er yndislegur tími. – Summer is a wonderful time.
And an oddball that doesn’t end in -legur, but that we all know and love
frá·bær adj – distinguished, excellent
ágætur adj – excellent, outstanding
Hann var ágætt skáld. – He was an outstanding poet.
It’s actually kind of nice that most of the adjective above end in -legur, because it makes it easy to focus on how one particular class of adverbs are formed, namely from those types of adjectives. And it’s quite easy, -legur becomes -lega, and you have the adverbial form. So
glæsilega – splendidly, magnificently
gríðarlega – enormously
rosalega – tremendously
And these adverbs in turn lead to intensifiers, words used to add even more emphasis to a sentence. The most common ones are probably mjög (very) or alveg (completely), but for variety you can use others like the ones above. A lot of times it may not be necessary to translate the intensifier literally, but just recognize it is being used for emphasis:
Það er rosalega gaman að heyra! – That is SO good to hear!
Gríðarlega spennandi bók. – An enormously exciting book.
So keep an eye out for these and other Icelandic words used to express just how absolutely fantastic and amazing something is