espantoso
frightful
espantar
to frighten
+
-oso
adjective suffix (full of)
Espantoso means frightful and can be thought of as espantar0 (to frighten0) + -oso1 (full of1), describing something full of the quality of frightening.
adjective
- frightfulCausing great fear, dread, or terrorLa película de terror era espantosa. // The horror movie was frightful.