antepretonic
/ˌæntiːˈprɛtɒnɪk/Definitions
1. adjective
relating to or occurring before the pretonic syllable in a word
“The term antepretonic is often used in phonetics to describe the sounds that occur before the main stress of a word.”
2. noun
a syllable or part of a word that occurs before the pretonic syllable
“The antepretonic syllable in ‘unimportant’ is ‘un-‘.”