-in-waiting
/ɪnˈweɪtɪŋ/combining form
1
- denoting a position as attendant to a royal personage表示“王室随从”：
lady-in-waiting.
2
- awaiting a turn, confirmation of a process, etc.等待（时机、过程确认等）的：
a political administration-in-waiting.
2.1
- about to happen即将发生的：
an explosion-in-waiting.