Syllable division derived from spelling — this word is not in the pronouncing dictionary, so no phonetic transcription is shown rather than a guessed one.
monstrously is an adverb meaning "in a hideous manner". It carries 3 recorded senses.
in a grotesque manner
“behind the house lay two nude figures grotesquely bald, with deliberate knife-slashes marking their bodies”
Definitions, synonyms and semantic relations for monstrously come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.