say it: TER-uh-blee
terribly is an adverb meaning "used as intensifiers". It carries 2 recorded senses.
used as intensifiers
“terribly interesting”
“I'm awful sorry”
colloquialism
Definitions, synonyms and semantic relations for terribly 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.