"Han er en vagt" means his profession.
"Han er vagt" is either somthing he is currently doing. Or the start of a sentens explaing where he works as a guard i.e. "Han er vagt i smykkebutikken" he is a guard at the jewllerystore
I have reported a bad pronunciation in this exercise.
Vagt is pronounced as in the meaning "weak" and not as in the correct meaning "guard".
It should be pronounced with a hard G.
And it should be "Han er vagt" and not "Han er en vagt".
It seems the pronunciation of VAGT in this sentence changes when you listen at normal speed versus when you listen at the slower speed. Which is the more common pronunciation for native danish speakers?