The phrase "dost the sly" means "you sneaky person" or "you cunning individual". If you are looking for synonyms for this phrase, you could use words like "devious", "sly", "cunning", "cagey", "crafty", "shrewd", "wily", "scheming", "calculating", and "manipulative". These words all convey the idea of someone who is not entirely trustworthy and who may use underhanded methods to gain an advantage over others. Whether you are describing a person's behavior or commenting on a situation that seems suspicious, these synonyms for "dost the sly" can help you express your thoughts more clearly and accurately.