This is the 12499th most frequent Swedish word.
skägg
Beard.
Here, 'skägg' is used as a noun referring to facial hair grown on the chin or cheeks.
Han har ett långt och tjockt skägg.
He has a long and thick beard.
In this sentence, 'skägget' refers to a specific beard, indicated by the definite form of the noun.
Skägget gör honom ser äldre ut än han verkligen är.
The beard makes him look older than he actually is.
Here, 'skägg' is used in the plural sense generically, referring to beards in general as a concept.