A loss, mistake, or failure resulting from an error or slip; an older/formal term often replaced by words like 'loss' or 'mistake'.
その判断ミスが会社に大きな損じをもたらした。
That mistaken decision caused a large loss for the company.
手続きの不備が損じにつながったので、再度確認した。
The procedural omission led to a loss, so we checked again.