An "inkhorn word" is an old-fashioned term for a pretentious, obscure, or overly academic word that ordinary people wouldn't typically use in conversation. Synonyms for this term might include "jargon," "pedantry," or "verbal ostentation." Other related words might include "sesquipedalian," which refers to excessively long words; "arcane," which means something is obscure or mysterious; or "pretentious," which implies an attempt to seem more important or impressive than one actually is. These words might be used to describe someone who is trying too hard to sound intelligent, or who is using words that are too obscure or specialized for the situation.