Breakdown of Dein Gesicht ist mir ganz unbekannt.
sein
to be
dein
your (informal)
mir
me / to me (dative)
ganz
quite, completely; whole
Questions & Answers about Dein Gesicht ist mir ganz unbekannt.
Why is the dative pronoun mir used here instead of the accusative mich?
The adjective unbekannt (unknown or unfamiliar) requires the dative case to show who it is unknown to. Just like with wichtig (important) or egal (indifferent), German uses the dative case with certain adjectives to express a personal perspective, making it mir unbekannt (unfamiliar to me).
Does ganz mean "whole" or "completely" in this sentence?
Here, it means "completely" or "entirely." When ganz is used as an uninflected adverb directly in front of an adjective like unbekannt, it intensifies that adjective. If it were instead used with a grammatical ending to modify a noun, it would mean "whole" (for example, ein ganzes Gesicht for "a whole face").
Why is mir placed before ganz unbekannt? Could I put it at the end?
You shouldn't put it at the end. In German sentence structure, pronoun objects like mir want to be placed as close to the conjugated verb (ist) as possible. The adverb ganz and the adjective unbekannt form a conceptual chunk that naturally takes the final position in this statement.
Can I drop the un- prefix and say Dein Gesicht ist mir bekannt?
Yes! bekannt is the exact opposite of unbekannt and means "known" or "familiar." Because it is the base adjective, it follows the exact same rule and governs the dative case. Saying Dein Gesicht ist mir bekannt simply means "Your face is familiar to me."