Keep a low profile: Stay out of public notice, avoid attracting attention to oneself. If someone keeps a low profile, they avoid doing things that will make people notice them.
Etymology：The term dates from the mid-1900s. William Safire suggests it may have originated in the military, where tanks and other armored vehicles are less vulnerable when they present a low profile. Another theory is that it is a translation of the Japanese teishisei, for “low posture,” the motto for Hayato Ikeda’s cabinet of 1960–64. It is now used in a large variety of contexts, ranging from politics (as in, “Let’s keep a low profile on abortion rights”) to celebrities in various fields.
中文释义：给我低调点! 保持低调，保持低姿态。这是一个非常常见的美国俚语,意思是不去引人瞩目,设法不引起人太多注意。例句：The government is trying to keep a low profile on this issue.（政府试图在这一问题上保持低姿态。）
under the radar：字面意思“在雷达下面”，原意表示在电子设备出现之前，军用飞机如果低空飞行避开雷达，就不会被发现；现在引申为“不引人注意，低调行事”。
2. have a high profile 引人注目，保持高调