This is the 1650th most frequent Dutch word.
onbekend
Unknown.
In this sentence, 'onbekend' is used as an adjective meaning 'unknown' to describe the subject, the origin of the painting.
De oorsprong van dat schilderij is onbekend.
The origin of that painting is unknown.
Here, 'onbekend' functions as an adjective meaning 'unfamiliar', modifying the noun 'situatie' to describe the newness or strangeness of the situation.
Hij voelde zich onzeker in een onbekende situatie.
He felt uncertain in an unfamiliar situation.
In this sentence, 'onbekend' is used adjectivally to mean 'uncharted' or 'not well-known', characterizing the domain as being unexplored or new to the subject.