This is the 6762nd most frequent Spanish word.
cormac
The word "cormac" is not Spanish; it is an Irish name.
In this sentence, 'Cormac' is used as a proper noun referring to the author Cormac McCarthy.
Cormac escribió 'La carretera', una novela impactante.
Cormac wrote 'The Road,' an impactful novel.
Here, 'Cormac' is again a proper noun, specifically referring to the same author, but this time in the context of discussing his works generally.
Acabo de leer un libro de Cormac.
I just read a book by Cormac.
In this example, 'Cormac' is used to attribute an artistic quality (his style) to the individual.