VERB 妨碍;阻碍 To militate against something means to make it less possible or likely. To militate against someone means to prevent them from achieving something.
Her background militates against her... 她的背景对她不利。
We can never promise to sail anywhere in particular, because the weather might militate against it. 天有不测风云,所以我们永远都无法保证会航行到哪个地方。