-eer
/ɪə(r)/suffix
1
- (forming nouns) denoting a person concerned with or engaged in an activity构成名词表示“与…有关的人”, “从事…的人”：
auctioneer
puppeteer.
2
- (forming verbs) denoting concern or involvement with an activity构成动词表示“与…有关”, “从事于”：
electioneer
profiteer.
词源
from French -ier, from Latin -arius; verbs (sense 2) are often back-formations （e.g. electioneer from electioneering）.