Jupa
Head — the tico word for the thing on your shoulders, and for the sense inside it.
Related lesson: Costa Rican Spanish: A Survival Guide.
Hear it in context
Me duele la jupa desde ayer.
My head's been hurting since yesterday.
Use la jupa, mae, eso no iba a funcionar.
Use your head, mate — that was never going to work.
Se pegó en la jupa con la puerta del carro.
He banged his head on the car door.
What It Actually Means
Jupa is the head — feminine, always definite (la jupa, mi jupa), and used both literally and for the reasoning that goes on inside it. It runs through the whole set of head expressions a language needs: headaches, bumps, and the instruction to think. Costa Ricans reach for it about as often as English reaches for “noggin”, and with roughly the same affectionate lack of dignity.
Where It Comes From
Probably indigenous, and honestly no further than that. The word is Costa Rican and Honduran, sits outside the Latin stock of Spanish body vocabulary, and is most often attributed to one of the Chibchan languages of the isthmus — but the attribution is a reasonable inference rather than a traced etymology, and reference works commonly file it as origin uncertain. Treat any confident single-source story you are told as folklore.
How Natives Use It
Informally, jokingly, and mostly about minor complaints and mild stupidity: me duele la jupa, use la jupa, anda mal de la jupa (he’s not right in the head). It sits comfortably with the rest of the register — “Diay mae, me duele la jupa” is three Costa Rican words in a row and a completely ordinary sentence.
Common Pitfall
It is jocular, not clinical. In a pharmacy or a doctor’s surgery the word is cabeza — walking into a consulting room complaining about your jupa lands somewhere between charming and unserious. And it does not travel: outside Costa Rica and its immediate neighbours you will simply not be understood.