A person who has been admitted or allowed to enter, such as a student admitted to a college or someone allowed into a club.
From admit plus -ee, a suffix meaning 'a person who receives the action.' The -ee suffix comes from French -é (past participle ending) and creates nouns for recipients of actions, as in employee, trainee, or refugee.
Admittee is built the opposite way from admitter—if an admitter is someone who lets you in, an admittee is someone who is let in. The -ee and -er suffixes are opposites, showing how English can flip meanings by swapping the ending!
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