hòu​bǔ

alternate

候补 (候補) hòu​bǔ
alternate adjective
a reserve candidate or substitute waiting to fill a position

He was elected as an alternate member in this election.

wait for vacancy verb
to wait to fill a vacancy or an opening, often in the context of employment or transportation

He is waiting for a standby seat for this sold-out flight.

Frequency

Movie subtitles
2.86 per million appears in 1% of films
Written text
1.33 per million

Sources

Definitions
CC-CEDICT