The phrase "in buckram" means to speak or act in a pompous, arrogant, or self-important way. This phrase may also be used to describe someone who is trying to impress others with their knowledge or abilities. Synonyms for "in buckram" include pretentious, haughty, snobbish, conceited, egotistical, ostentatious, showy, grandiose, and affected. Using these synonyms can help to add variety to your writing and better describe the behavior of someone who is being overly boastful or putting on airs. Remember to choose the most appropriate synonym based on the context and tone of your writing.