This is the 172nd most frequent Icelandic word.
maður
The Icelandic word "maður" means "man" or "person" in English.
Here, 'maður' is used to denote 'a man', referring to an individual person (countable noun).
Maður gengur á fjöllum.
A man is hiking in the mountains.
In this case, 'maður' is used in a generalized sense, equivalent to 'one' in English, indicating a person in an indefinite manner.
Maður verður að vera forsjáll.
One must be prudent.
Here, 'maður' is again used in the general sense of 'one', referring to people in general and actions broadly applicable.