(~s)
1.
An ~ is someone who holds an official post at a particular time. (FORMAL)
In general, ~s have a 94 per cent chance of being re-elected.
N-COUNT
•
Incumbent is also an adjective.
...the only candidate who defeated an ~ senator.
ADJ: ADJ n
2.
If it is ~ upon you to do something, it is your duty or responsibility to do it. (FORMAL)
It is ~ upon all of us to make an extra effort.
ADJ: it v-link ADJ upon/on n to-inf