Ο συμπρωταγωνιστής παίζει τον δευτερεύοντα ρόλο.

συμπρωταγωνιστής means co-star or fellow lead actor.

It is made up of:

• συν-/συμ- = with, together
• πρωταγωνιστής = leading actor, protagonist

So συμπρωταγωνιστής is someone who stars alongside another main actor.

Ο is the masculine singular definite article in the nominative case. It means the.

Here it goes with συμπρωταγωνιστής:

• Ο συμπρωταγωνιστής = the co-star

Greek articles change for gender, number, and case, unlike English the, which never changes.

Because this phrase is the object of the verb παίζει.

In English:

• The co-star plays the supporting role.

Here:

• The co-star = subject
• the supporting role = direct object

In Greek, the direct object usually takes the accusative case.

So:

• nominative: ο δευτερεύων ρόλος
• accusative: τον δευτερεύοντα ρόλο

Both the article and the words connected to it change form to show the accusative.

Here is the case breakdown:

• Ο συμπρωταγωνιστής → nominative
  This is the subject, the one doing the action.

• τον δευτερεύοντα ρόλο → accusative
  This is the direct object, the thing being played.

This is one of the biggest differences from English: Greek often shows grammatical function through case endings.

Because ρόλος is in the nominative singular, while ρόλο is in the accusative singular.

For many masculine nouns ending in -ος:

• nominative singular: -ος
• accusative singular: -ο

So:

• ο ρόλος = the role
• τον ρόλο = the role (as object)

This is very common in Greek:

• ο φίλος → τον φίλο
• ο δρόμος → τον δρόμο

Because it has to match ρόλο in gender, number, and case.

The adjective δευτερεύων means secondary / supporting. Its masculine forms include:

• nominative singular: δευτερεύων
• accusative singular: δευτερεύοντα

Since ρόλο is:

• masculine
• singular
• accusative

the adjective must also be:

• masculine
• singular
• accusative

So:

• ο δευτερεύων ρόλος
• τον δευτερεύοντα ρόλο

Here παίζει means plays in the acting sense: performs the role of.

It is the:

• 3rd person singular
• present tense
• of the verb παίζω

So:

• παίζω = I play
• παίζεις = you play
• παίζει = he/she/it plays

Important: παίζω can mean different things depending on context, such as:

• play a game
• play music
• act / play a role

In this sentence, because of ρόλο, it clearly means play a role.

Yes. Greek often does not need to use a separate subject pronoun like he or she, because the verb ending already gives that information.

Here:

• παίζει already means he/she/it plays

But the sentence also has the explicit subject:

• Ο συμπρωταγωνιστής

So the full meaning is:

• The co-star plays the supporting role.

In Greek, παίζω can take a direct object without any extra preposition.

So Greek naturally says:

• παίζει τον ρόλο = plays the role

If you want to specify whose role, Greek often uses:

• παίζει τον ρόλο του... = plays the role of...

Example:

• Παίζει τον ρόλο του πατέρα. = He plays the role of the father.

But in your sentence, τον δευτερεύοντα ρόλο already functions as the direct object, so no extra preposition is needed.

• πρωταγωνιστής = protagonist / leading actor / main star
• συμπρωταγωνιστής = co-star, someone who stars together with another main actor

So συμπρωταγωνιστής suggests a person who is important in the cast, but not necessarily the single main star.

Yes, Greek word order is more flexible than English because case endings show who is doing what.

The neutral/basic order here is:

• Ο συμπρωταγωνιστής παίζει τον δευτερεύοντα ρόλο.

But other orders are possible, for example:

• Τον δευτερεύοντα ρόλο παίζει ο συμπρωταγωνιστής.

That version gives more emphasis to the supporting role.

English usually relies much more on word order, while Greek can use both word order and case endings.

A rough pronunciation guide is:

O simprotagonistís pézi ton devterévonda rólo

A few notes:

• Ο sounds like o in or but shorter
• συμ- before π sounds like sim-
• γ in συμπρωταγωνιστής is a normal g sound here because it is part of -αγ-
• παίζει sounds roughly like PEH-zee
• τον is usually pronounced ton
• ρόλο is RO-lo

The stressed syllables are marked by the written accents:

• συμπρωταγωνιστής
• παίζει
• δευτερεύοντα
• ρόλο

Yes, you can, depending on context.

• τον δευτερεύοντα ρόλο = the supporting role
• δευτερεύοντα ρόλο = a supporting role or a less specific supporting role

Greek often uses the article more than English, but dropping it can make the noun phrase less definite.

So:

• Ο συμπρωταγωνιστής παίζει τον δευτερεύοντα ρόλο.
  = The co-star plays the supporting role.

• Ο συμπρωταγωνιστής παίζει δευτερεύοντα ρόλο.
  = The co-star plays a supporting role.

It can be used more generally too.

Literally, here it means supporting role in acting. But Greek also uses παίζω ... ρόλο in a broader, figurative way, like English play a role.

Example:

• Η τύχη παίζει σημαντικό ρόλο. = Luck plays an important role.

So ρόλος can refer to:

• an acting role
• a social role
• a function or part in a situation

In your sentence, because of συμπρωταγωνιστής, the acting meaning is the natural one.