This is the 8772nd most frequent Russian word.
поддубко
The word "поддубко" does not appear to have a standard definition in Russian; it may be a rare term, a misspelling, or a colloquialism.
In this sentence, "Поддубко" is used as a proper noun, likely a surname, referring to a person.
Поддубко использовал свои знания на практике.
Poddubko used his knowledge in practice.
Here, "Поддубко" is a surname mentioned within the context of a biographical reference.
Я прочитал книгу о жизни Ивана Поддубко.
I read a book about the life of Ivan Poddubko.
In this instance, "Поддубко" again is a proper noun, referring to a notable individual, likely Ivan Poddubko, within a cultural or historical context.