On the noun אִישׁ in Judges 19:23

(The above rendering comes from the RJPS translation, an adaptation of the NJPS translation. Before accounting for this rendering, I will analyze the plain sense of the Hebrew term containing אִישׁ.)

Prototypically, אִישׁ is used in sketching a situation schematically. Here, it performs its basic function of labeling a referent in terms of the situation of interest. That is, אִישׁ is not used to make gender contrasts (except when paired with its counterpart feminine form, to refer to social categories of persons); that’s what the nouns גֶּבֶר and זָכָר are for. Rather, הָאִישׁ is the standard way to point to someone as being the aforementioned salient participant in the situation at hand. (The narrator likewise uses it in this way below, in v. 25.) Yes, the speaker is making a distinction based on gender, but his choice of label here is hardly contributing to that message.

As for rendering into English, nowadays the NJPS ‘this man’ overstates gender. And in this highly gendered context, it creates a misleading impression that the Hebrew is contrasting male with female. The revised rendering follows the time-honored practice of employing an English relational noun (in this case, ‘fellow’) to more closely convey the situation-oriented Hebrew term; see further at the end of my comment at Joshua 10:24.