妨碍 (fáng ài) means to hinder or interfere with, especially abstract progress, order, or someone's rest. It is close to 阻碍 (zǔ ài) but 阻碍 can also be a noun, and 妨碍 is more about causing inconvenience rather than fully blocking. Unlike 耽误 (dān wu) which stresses delay, or 挡 (dǎng) which is for physical blocking.