If you are going to visit me in a flying machine some day (you do not have to hurry) then “takk” is a very good word to know.
It means "thank you".
My people like to say it very much, and they also like to hear it.
Sometimes they say “þakka þér fyrir”, but when they are in a hurry they prefer “takk” because it has fewer letters in it.
If you tell one of them that he or she is looking very good today, they will probably say this to you. They might also think you are up to something.
(Ó, and I almost forgot. It is also the name of a famous geisla-diskur.)