Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
pestilent is an adjective meaning "exceedingly harmful". It carries 2 recorded senses.
exceedingly harmful
likely to spread and cause an epidemic disease
“a pestilential malignancy in the air”
“plaguey fevers”
Definitions, synonyms and semantic relations for pestilent come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.