malpais
/malpɑːˈiːs/Usually US regional (south-western )
noun
1Rugged or difficult country of volcanic origin; a region of bare solidified lava.
2Basaltic lava.
Origin
Mid 19th century; earliest use found in George Kendall (1809–1867), editor and journalist. From Spanish mal país from malo bad (from classical Latin malus: see mal-) + país country.