This is the 13725th most frequent Polish word.
podobnego
"Podobnego" means "similar" or "like" in English.
In this sentence, 'podobnego' is used as an adjective describing 'nic' (
Nie widziałem nic podobnego wcześniej.
I haven't seen anything similar before.
Here, 'podobnego' acts as an adjective relating to 'kogoś' (someone)
Czy znasz kogoś podobnego do Anna?
Do you know someone similar to Anna?
'Podobnego' is used to describe 'czegoś' (something) indicating resemblance