Example: My teacher used an extinguisher.
The Suffix -er Teacher vs. Extinguisher Learn Suffixes English Language Learning Tips Video
(added to verbs) person or thing that does an action indicated by the root verb; used to form an agent noun.
reader, cooker, computer, runner-up, do-gooder
(added to a noun denoting an occupation) Person whose occupation is (the noun).
astrologer, cricketer, trumpeter
(added to a number, measurement or noun denoting a quantified set) A name for a person or thing that is based on a number (with or without a noun).
sixer, six-footer, three-wheeler, first-grader
(slang, chiefly entertainment, with few limitations) Used to form nouns shorter than more formal synonyms.
percenter (commission agent); one-hander (one-man show); oater (a Western-themed movie)
(informal, added to a noun) One who enjoys.
Tooners lined up for tickets to Toy Story.
(derogatory, added to nouns) Person who subscribes to a particular conspiracy theory or unorthodox belief.
anti-vaxxer, birther, flat-Earther, 9/11 truther
Mastering A, An, The: English Articles Solved:
My Website (PDF): http://www.eslprofessor.com
Photo Credit: http://commons.wikimedia.org/wiki/User:Cjp24