This is the 8576th most frequent Dutch word.
hoofdzakelijk
Mainly; primarily.
In this instance, 'hoofdzakelijk' is used as an adverb to indicate that writing is the primary activity the subject is engaged in.
Hij houdt zich hoofdzakelijk bezig met schrijven.
He mainly focuses on writing.
Here, 'hoofdzakelijk' acts as an adverb describing the primary topic discussed in the meeting.
De vergadering ging hoofdzakelijk over de financiën.
The meeting was mainly about finances.
In this sentence, 'hoofdzakelijk' is used to suggest that vegetables and fruits comprise the majority of their diet.