A person who expects something; one who waits for or anticipates an outcome.
From expect plus -er (one who does the action). While logically sound, this word is extremely rare; English speakers prefer 'person who expects' or 'one expecting.'
Even though 'expecter' is grammatically perfect, it's so uncommon that many dictionaries don't list it. It's a ghost word in English—something that should exist by all the rules but almost never gets used.
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