noun, masculine/puˈpu/
poop; poo
““La bebé pasó todo el día haciendo pupú, la llevé al hospital que está cerca de mi casa, le pusieron tratamiento pero no mejoró”.” — “The baby spent all day pooping, I took her to the hospital that's near my house, they gave her treatment but she didn't improve”.
Related: puputov
Likely onomatopoeic. Compare with popó.