1. （坐、立的）姿势，姿态
    Your posture is the position in which you stand or sit.

posture的近义词

    e.g. You can make your stomach look flatter instantly by improving your posture...
           通过采取更好的坐姿，你的腹部马上就会看起来平坦一些。
    e.g. Exercise, fresh air, and good posture are all helpful...
           锻炼、新鲜空气和好的坐立姿势都很有益。

2. 态度；立场
    A posture is an attitude that you have towards something.

posture

    e.g. The military machine is ready to change its defensive posture to one prepared for action...
           军方随时准备由防御立场转向备战立场。
    e.g. None of the banks changed their posture on the deal as a result of the inquiry.
           没有一家银行因为这次调查而对该交易改变立场。

3. 故作姿态；装腔作势；装模作样
    You can say that someone is posturing when you disapprove of their behaviour because you think they are trying to give a particular impression in order to deceive people.

    e.g. She says the President may just be posturing.
           她说总统也许只是在做样子而已。