"Six one half a dozen of other" is an idiom that means there is no significant difference between two options being compared. Some synonyms for this idiom include "six of one, half dozen of the other," "much of a muchness," "equally likely," "equally valid," and "no better or worse." These phrases are often used to convey a sense of indifference or confusion when faced with a choice where both options seem equally appealing or unappealing. The phrase "tomato, tom-ah-to" can also be used as a synonym, indicating that two words or ideas different only in pronunciation are essentially the same.