וְאַבְשָׁל֗וֹם וְכׇל־הָעָם֙ אִ֣ישׁ יִשְׂרָאֵ֔ל בָּ֖אוּ יְרוּשָׁלָ֑͏ִם וַאֲחִיתֹ֖פֶל אִתּֽוֹ׃
Meanwhile Absalom and all the troops, Israel’s force, arrived in Jerusalem, together with Ahithophel.
(The above rendering comes from the RJPS translation—an adaptation of the NJPS translation—as slightly modified in October 2023. Before accounting for this rendering, I will analyze the plain sense of the אִישׁ term, by employing a situation-oriented construal as outlined in “Notes on Gender in Translation,” pp. 11–16.)
When a referring expression includes אִישׁ, that noun prototypically marks its referent’s defining participation in the depicted situation. This remains true when אִישׁ is in construct with a group name, such as אִישׁ יִשְׂרָאֵל. Here, in the context of intragroup hostilities, it labels the militia in terms of their being a constitutive party to the coup d’état. The militia’s members are construed as a unit—hence the singular noun. This usage regards them as one of the two opposing sides. This is one of the instances where a “collective” construal of אִישׁ is evident grammatically, from the apposition with the collective term עָם.
On the meaning of this conventional usage in the context of hostilities, see further my comment at Josh 10:24.
As for rendering into English, see my comment at Josh 10:24. Meanwhile, the fact that women are not in view is self-evident from the military context.