Feliz cumpleaños, amiga.

Happy birthday, friend.

Breakdown of Feliz cumpleaños, amiga.

• la amiga: the friend
• feliz cumpleaños: happy birthday

Questions & Answers about Feliz cumpleaños, amiga.

Why is there no verb in Feliz cumpleaños, amiga?

Because this is a fixed greeting, just like English Happy birthday! Spanish often leaves out words that are understood from context.

So Feliz cumpleaños works as a complete expression even without a verb like I wish you or have.

Why does cumpleaños look plural if it refers to one birthday?

Cumpleaños is a special noun. It comes from the idea of cumplir años—literally, to complete/turn years. Even when talking about one birthday, the word stays cumpleaños.

So:

• el cumpleaños = the birthday
• los cumpleaños = the birthdays

The form itself does not change between singular and plural; the article or context tells you which one it is.

Why is feliz singular if cumpleaños ends in -s?

Because in this sentence cumpleaños is being treated as a singular noun: one birthday.

So the adjective is singular too:

• feliz cumpleaños = singular idea

If you really needed a plural adjective, feliz becomes felices, but in the standard birthday greeting to one person, feliz is correct.

What does amiga mean grammatically here?