-er

1. 1. One that performs a specified action: swimmer.
   2. One that undergoes or is capable of undergoing a specified action: broiler.
   3. One that has: ten-pounder.
   4. One associated or involved with: banker.
2. 1. Native or resident of: New Yorker.
   2. One that is: foreigner.

[Middle English, partly from Old English -ere (from Germanic *-ārjaz , from Latin -ārius, -ary), partly from Anglo-French -er (from Old French -ier , from Latin -ārius) and partly from Old French -ere, -eor; see -or¹.]