say it: spahn-TAY-nee-uh-slee
spontaneously is an adverb meaning "in a spontaneous manner". It carries 2 recorded senses.
in a spontaneous manner
“this shift occurs spontaneously”
Definitions, synonyms and semantic relations for spontaneously 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.