mission creep
noun [ U ] disapproving uk/ˈmɪʃ.ən ˌkriːp/ us/ˈmɪʃ.ən ˌkriːp/
（尤指军事行动中的）使命偏离，任务蠕升
the fact of doing a much larger job for a longer time than was originally expected, especially in a military operation
江苏热线英汉汉英双解词典包含207361条英汉翻译词条，涵盖了常用英语单词及词组短语的翻译及用法，是英语学习的必备工具。