This is the 103rd most frequent Afrikaans word.
pretorius
"Pretorius" is not a standard Afrikaans word; it is a proper noun, typically a surname.
Here, 'Pretorius' is being used as a proper noun, specifically a surname.
Pretorius is 'n gewilde van in Suid-Afrika.
Pretorius is a common surname in South Africa.
This usage associates 'Pretorius' metaphorically with a characteristic, implying a person enjoys fun, showing extended use of a surname to idiosyncratically denote personality traits.
'n Gaan pretorius kan beteken iemand wat van pret hou.
'A Pretorius' can mean someone who enjoys fun.
In this sentence, 'pretorius' is used informally as an adjective to mean 'enjoyable' or 'full of fun', which is a creative use not standardized in formal Afrikaans.