She played an active role in the women's liberation movement.
Literal
She [topic-は] women's-liberation-movement [in-で] actively was-active.
婦人解放運動 ('women's liberation movement') is a Sino-Japanese compound. 積極的に ('actively/proactively') uses the ~的 suffix. 活躍する ('to play an active role') is a strong verb for impactful participation.