Learn Hardcore Polish: Ten zawodnik jest mocny i dobrze broni. - This player is strong and defends well.

Ten is a demonstrative adjective. In this sentence it means this or that, depending on context, but very often in natural English the sentence is simply translated as The player is strong and defends well.

Polish uses ten / ta / to to point something out:

ten zawodnik = this/that player
ta kobieta = this/that woman
to dziecko = this/that child

Here, zawodnik is a masculine noun, so ten is the correct form.

Why is it ten zawodnik and not to zawodnik?

Because zawodnik is a masculine singular noun, and the demonstrative has to agree with it in gender and number.

The basic nominative forms are:

ten for masculine
ta for feminine
to for neuter

So:

ten zawodnik = this player
ta zawodniczka = this female player/athlete
to dziecko = this child

English does not make this kind of agreement, but Polish does.

What exactly does zawodnik mean?