N. Amer. informal <北美, 非正式>
an advance warning of something
预警, 事先警告：
the heads-up came just in time to stop the tanks from launching the final assault.
预警正好及时收到, 从而阻止了坦克发动的最后进攻。
attrib.
showing alertness or perceptiveness
机警的, 警觉的; 有洞察力的：
they played a very heads-up game.
他们打得很有智谋。