special interest group
noun [ C ] uk/ˌspeʃ.əl ˈɪn.trest ˌɡruːp/ us/ˌspeʃ.əl ˈɪn.trɪst ˌɡruːp/ (US also special interest)
（企图影响政治决策来满足自身特定需求的）特殊利益集团
a group of people who have particular demands and who try to influence political decisions involving them
Much of the pressure for changing the law has come from special interest groups. 要求变革法律的压力有很大一部分来自于特殊利益集团。