Similar words
anonym
Anonym is anonymous — identity deliberately hidden; unbekannt is simply unknown, with no implication that it's being hidden on purpose.
Similar in other languages
Spanish
desconocido
desconocido is the Spanish word for the same thing — both mean "unknown."
Spanish
ignoto
ignoto is the Spanish word for the same thing — both mean "unknown."
Spanish
incógnita
incógnita is the Spanish word for the same thing — both mean "unknown."
Practice
1 What does unbekannt mean?
unknown
2 Fill the gap: Der Absender war ___.
Full sentence: Der Absender war unbekannt. (The sender was unknown.)
3 Which fingerprint chart matches unbekannt?
unbekannt: neutral register, core frequency, general domain, neutral connotation.