La jugadora de fútbol es muy tranquila.

Spanish nouns that refer to people often change ending to mark gender.

• el jugador = the (male) player
• la jugadora = the (female) player

Because we’re talking about a female soccer player, the feminine form la jugadora is used. Both words come from the verb jugar (to play).

Adjectives in Spanish must agree in gender and number with the noun they describe.

• Noun: jugadora → feminine, singular
• Adjective: tranquila → feminine, singular to match

If the noun were masculine:

• El jugador de fútbol es muy tranquilo.
  “The (male) soccer player is very calm.”

So:

• masculine singular: tranquilo
• feminine singular: tranquila
• masculine plural: tranquilos
• feminine plural: tranquilas

No, that would be incorrect.

Tranquilo is masculine, but jugadora is feminine, so they don’t agree.
You must use tranquila to match the feminine noun:

• ✅ La jugadora de fútbol es muy tranquila.
• ❌ La jugadora de fútbol es muy tranquilo.

Both are grammatically correct, but the nuance changes:

• es muy tranquila → describes a general, typical characteristic
  
  • “She is (by nature) very calm / laid-back.”
• está muy tranquila → describes a current, temporary state
  
  • “She is very calm (right now / at this moment).”

So:

• Use es for personality traits.
• Use está for how she is feeling or acting now.

In Spanish, when you describe what kind of player someone is, you usually use de + noun:

• jugadora de fútbol = soccer player
• jugador de baloncesto = basketball player
• jugador de tenis = tennis player

You normally cannot just put the second noun directly after the first like in English (“soccer player”). You need de to connect them.

No, another very common word is futbolista:

• la futbolista = the (female) soccer player
• el futbolista = the (male) soccer player

Futbolista is a common-gender noun: the form stays the same, and you change only the article:

• el futbolista (man)
• la futbolista (woman)

In Latin America, jugadora de fútbol and futbolista are both widely understood.

No, not in this sentence. You need the article:

• ✅ La jugadora de fútbol es muy tranquila.

Without la, it sounds incomplete or wrong.

You can drop the article in some special cases, like short labels or headlines, but for a normal full sentence referring to a specific person, the article is required.

Tranquila can mean:

• calm, not easily upset
• peaceful, relaxed
• quiet, not noisy
• laid-back / chill (informally)

In this sentence, it most naturally suggests a personality trait:
She’s a calm / laid-back person, not very nervous or aggressive.

It does not specifically mean “shy” (that would be more like tímida), though a tranquila person might also be shy.

You can say calmada, but the nuance is slightly different:

• tranquila → very common for personality; sounds natural as a trait
• calmada → more often used for a current state (“she has calmed down”), or when contrasting with being nervous or agitated

For a general character description, tranquila is more standard and frequent.

Muy always goes before the adjective or adverb it modifies:

• ✅ es muy tranquila
• ❌ es tranquila muy

Other examples:

• muy alto (very tall)
• muy rápido (very fast)
• muy simpática (very nice)

So the correct structure is:
[form of ser/estar] + muy + adjective

Yes, you can, but the meaning and style change slightly.

• La jugadora de fútbol es muy tranquila.
  Neutral, simple statement about her personality.

• La tranquila jugadora de fútbol…
  Adjective before the noun is more literary or descriptive and can sound slightly more expressive or stylistic, like in written narratives.

In everyday speech, for basic descriptions, adjectives like tranquila usually come after the noun or after the verb ser/estar.

You’d make the noun and adjective plural:

• Las jugadoras de fútbol son muy tranquilas.
  
  • las → plural feminine article
  • jugadoras → plural of jugadora
  • son → plural of es
  • tranquilas → plural feminine adjective

So:

• Singular: La jugadora de fútbol es muy tranquila.
• Plural: Las jugadoras de fútbol son muy tranquilas.

Fútbol comes from English “football,” but it follows Spanish stress rules:

• It’s written fútbol to show the stress is on the first syllable: FÚT-bol.
• Without the accent (futbol), by regular rules the stress would fall on the last syllable (fut-BOL), which is not correct.

So the accent mark tells you how to pronounce it properly in Spanish.