1. 骇人的;令人震惊的
Something that is horrendous is very unpleasant or shocking.

2. （数量、程度等）大得惊人的，极其过分的
Some people use horrendous to describe something that is so big or great that they find it extremely unpleasant.

1. causing fear or dread or terror

e.g. 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

Synonym: awfuldiredirefuldread(a)dreadeddreadfulfearfulfearsomefrighteninghorrificterrible