This is the 4405th most frequent German word.
gänzlich
Entirely; completely.
In this sentence, 'gänzlich' is used as an adverb to intensify the verb 'überrascht', denoting the totality of the surprise.
Er war gänzlich überrascht von der Nachricht.
He was completely surprised by the news.
Here, 'gänzlich' describes the complete constitution of the building's material, emphasizing its entirety.
Das Gebäude ist gänzlich aus Holz gebaut.
The building is entirely made of wood.
In this context, 'gänzlich' functions to express full agreement, indicating no reservation in the statement.