This is the 527th most frequent Polish word.
pojawił
"Appeared" (past tense of "appear").
Here, 'pojawił' means that the moon has started to be visible in the sky.
Na niebie pojawił się księżyc.
The moon appeared in the sky.
In this context, 'pojawił' indicates the introduction of someone new to the family setting.
W naszym życiu pojawił się nowy członek rodziny.
A new family member appeared in our life.
Here, 'pojawił' is used to signify the sudden availability or introduction of items in the store.