This appears to be a corrupted or extremely obscure technical term with no clear definition in standard dictionaries.
Possibly a compound combining Hermogenian with an unclear suffix; likely a printing error, manuscript corruption, or specialized jargon.
Sometimes words in historical texts are so garbled that even expert lexicographers throw up their hands—this might be one of those mysteries!
Complete word intelligence in one call. Free tier — 50 lookups/day.