de mercado persa

Question

Vivía perpetuamente adherido a una pipa apagada que desprendía efluvios de mercado persa y se describía a sí mismo como el último romántico.

Again, this is from La sombra del viento. My attempt: He lived perpetually attached to an unlit pipe that gave off the scent of a Persian market, and he described himself as the ultimate romantic.

Why doesn't persa change its ending to match mercado? How do I know -- just because it is entered in the dictionary as persa and not perso? Are there any other words like this? (Hint: I hope not )

Answer 1

Es un sustantivo/adjetivo común en cuanto al género, y como este hay muchos (más de 1000):

olmeca, inca, carioca, homicida, suicida, terrícola, atleta, poeta, asceta,...

Answer 2

Thank you. I'd just never come across this before.

Answer 3

I think you've answered your own question. There is no word perso in this meaning, so there is no gender disagreement. There are quite a few words like this in Spanish, one example being used in the popular beer Negra Modelo. It's negra because cerveza is feminine, but modelo because there is no modela.