"不带女伴的舞客" can be translated into English as "a dancer without a female partner" or, more colloquially, "a single dancer (without a female companion)".
If the context implies a social dance setting where couples are expected, you could also say "a dancer attending without a female dance partner" or "a dancer without a plus-one (female)" (though "plus-one" is more neutral about gender, it can be adapted to clarify if needed).
For a more concise and context-appropriate option in a dance or social setting: "a dancer without a female escort/partner".
Choose based on the specific nuance you want!