In 则无迟重之虞所谓顶头悬也, does 顶头悬 translate to "Incoming Danger"?
There is a detailed explanation of 顶头悬  here

就是要求习拳之人在打拳时，要将头部向上轻轻顶起，以使身姿挺拔，立身中正，意念集中，精神贯注。


it is required that the person practicing Tai Ji should gently lift his head upwards to make the posture straight, stand upright, focus on the mind, and concentrate.

顶头悬 describes &quot;lift one's head&quot; (make one's neck touch his collar, chin slightly pull inward)

顶 = top

头 = head

悬 = hang up / lift



顶头悬 can be called &quot;lift head&quot; or &quot;straighten head &quot;. It is the name of a 姿勢 (posture)

The idea is: when your head is straight, the rest of your body would also be in good form