"Dost a number" is a slang term that means to deceive or betray someone. The antonyms for this term would be words that represent honesty and loyalty. Words such as "trustworthy," "dependable," and "faithful" would be good examples. Another way to express the opposite of "dost a number" would be to use phrases such as "stay true to," "be honest with," or "keep one's promises." Using these antonyms and alternate phrases is a great way to ensure clear communication and avoid any misunderstandings in various situations, particularly in personal relationships and professional settings.