The spelling of the word "most innerving" can be a bit confusing, but with the help of IPA phonetic transcription, it becomes clearer. The word is spelled with an "i" rather than an "e" because the sound is closer to /ɪ/ than /ɛ/. The first syllable is stressed, which is indicated by the accent mark. The word "innerving" itself means to stimulate or excite, and when combined with "most," it becomes a superlative form indicating the highest level of stimulation.