Antonyms for the word "branch of knowledge" could be "ignorance," "unfamiliarity," and "inexperience." Ignorance refers to a lack of knowledge or information about a particular subject. Unfamiliarity suggests a lack of understanding or acquaintance with a specific area of study. Inexperience pertains to a lack of practical knowledge or skills in a particular field. These antonyms highlight the opposite of having a deep understanding and expertise in a particular area of study. Thus, it is crucial to increase our knowledge and develop expertise regarding various domains, eliminating ignorance, unfamiliarity, and inexperience.