In common usage, "terrific" is one of those
words in the
English language that is
paradoxically its own
antonym. It can mean "
very good" or "
very bad."
For example, you can say "I've got a terrific
headache" or "I had a terrific
vacation." Note that
neither of these
usages
corresponds to its
literal meaning.
See Words That Are Their Own Antonyms.
This information shamelessly ripped-off from Car Talk