1(forming nouns) denoting a person concerned with or engaged in an activity.‘auctioneer’‘puppeteer’
2(forming verbs) denoting concern or involvement with an activity.‘electioneer’‘profiteer’
From French -ier, from Latin -arius; verbs are often back-formations (e.g. electioneer from electioneering).
We take a look at several popular, though confusing, punctuation marks.