掳 is a bound form — it doesn't stand alone in modern Chinese. Common compounds: 掳走 (to abduct/carry off), 掳掠 (to plunder and take captives), 掳获 (to capture).
The hand radical, side-form of 手, marks 掳 as a physical action done with the hands — here the violent grabbing of captives. It groups the character with 抓、抢、拘 in the wider seizing-and-restraining family.
Carries the sound lǔ unchanged and reinforces the meaning, since 虏 by itself already means a war captive. 掳 is essentially 虏 made vivid by the hand radical — a captor's hand actively dragging the prisoner away.
