"不带女伴的舞客" can be translated into English as "a dancer without a female partner" or, more commonly in the context of a social dance event, "a single dancer (without a partner)" or "a dancer attending without a female companion".
For a more concise and idiomatic expression, you might also say "a dancer without a dance partner" (though this doesn't specifically mention gender, it's generally understood in the context of a dance where partners are typically of opposite genders), or "a solo dancer at the event" (if the context implies that most dancers attend with partners).
However, if you specifically want to emphasize the absence of a female companion, "a dancer without a female partner" is the most straightforward translation.