The phrase "lowdown and dirty" typically implies unethical or immoral behavior. Antonyms for this phrase might include words such as honorable, upstanding, straightforward, or transparent. These opposite words suggest a sense of integrity and honesty rather than deceitfulness or underhandedness. Similarly, terms like clean, pure, or wholesome could be interpreted as antonyms to "dirty," indicating cleanliness and clarity over grime and obscurity. Using antonyms to "lowdown and dirty" can add a sense of positivity and morality to language, emphasizing the importance of ethical behavior in all aspects of life.