“脱党者”可以翻译为 "those who have resigned from the Party" 或 "defectors from the Party"。
"those who have resigned from the Party" 强调主动退出党组织的行为，较为中性。
"defectors from the Party" 侧重于描述背离组织的行为，可能带有更强烈的负面色彩。
根据具体语境选择合适的表达即可。