Working Lady is a euphemism for a female prostitute. It is preferred by many sex workers and members of the public because it does not carry the negative connotations of many other terms used to classify a person in this line of sex work.
The term working lady is often shortened to the acronym WL.
More About Working Lady (WL)
Working Lady is one of the many terms used to describe a prostitute, and is also one of the most flattering. Unlike many terms used to describe a prostitute, working lady does not carry with it any negative connotations about a woman's status or promiscuity. It also emphasizes that the woman is simply making a living and gives no judgment about how it is done.
The choice of the word 'lady' carries connotations of nobility and refinement. The term Working Lady suggests a more mature and respected sex worker than the other similar, common term Working Girl.
Though less commonly used, the term Working Man may also be used to classify a male sex worker or prostitute.