gusano

worm; insect larva, such as a grub, caterpillar, or maggot; worm, low person; Cuban reactionary or counter-revolutionary

“gusano de seda” — silkworm

Inherited from Old Spanish gusano, of further uncertain origin. Possibly from Latin cossus (with an additional suffix), according to the Diccionario de la lengua española of 1884, but this is highly unlikely. Possibly from Paleo-Hispanic. Unrelated to Russian гу́сеница (gúsenica, “worm”). In the sense of "counter-revolutionary" or "reactionary" it can be attributed to Fidel Castro.