say it: haw-REN-duhs
horrendous is an adjective meaning "causing fear or dread or terror". It carries one recorded sense.
causing fear or dread or terror
“the awful war”
“an awful risk”
“dire news”
“a career or vengeance so direful that London was shocked”
“the dread presence of the headmaster”
“polio is no longer the dreaded disease it once was”
“a dreadful storm”
“a fearful howling”
“horrendous explosions shook the city”
“a terrible curse”
Definitions, synonyms and semantic relations for horrendous come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.