IPA: /ʌnˈɒbzɜːvd/
KK: /ʌnˈɑːbˌzɜːrvd/
Not seen or noticed by anyone.
The unobserved bird quickly flew away when it sensed danger.
In a manner that is not seen or noticed by anyone.
The thief left the scene unobserved, making it difficult for the police to find any evidence.
Unobserved → It is formed from "un-" (meaning not) and "observed" (from Latin "observare", meaning to watch or pay attention to). The word "unobserved" means not being watched or not having attention paid to.
Think of 'not' ('un-') watching or paying attention to something ('observed'). This helps you remember that 'unobserved' means something that is not being watched.