The phrase "doeth one bit" refers to a person who puts in some effort or undertakes a task to some extent. The antonyms for this phrase include terms like "neglect," "ignore," "shirk," and "avoid." These words denote a lack of action or responsibility towards a task or project. By contrast, synonyms for "doeth one bit" include terms like "participate," "contribute," "pitch in," and "help out." These words suggest an active engagement with the task or project at hand. Therefore, based on the context, one can use antonyms or synonyms for "doeth one bit" to convey the appropriate meaning.