隐蔽
yǐn bì · HSK 7
to conceal
🥷 隐 hidden + 蔽 to cover/shelter = covered up so it can't be seen
隐 means hidden or concealed; 蔽 means to cover or shield (think a screen blocking the view). Together 隐蔽 is the deliberate covering-up that keeps something covert or under cover.