Quietly or obediently, without concern for or knowledge of some danger or trouble that one is facing. An uncommon variant of "like a lamb to (the) slaughter." When I worked with Michael, he manipulated me into venturing into all sorts of shady and downright illegal ventures, like a pig to the slaughter. The poor kid and his defense team had no idea what the prosecution had in store—it was like a pig to the slaughter the moment the trial began. The six employees were unaware the meetings were to tell them they'd been laid off, and they each marched down to the meeting room like a pig to slaughter.