Real Dictionary

hypercorrection in American English
a nonstandard usage resulting from an overly conscious effort to avoid an error, as in the case of personal pronouns (Ex.: “between you and I”)
noun: the substitution, in an inappropriate context, of a pronunciation, grammatical form, or usage thought by the speaker or writer to be appropriate, resulting usually from overgeneralizing in an effort to replace seemingly incorrect forms with correct ones,

hypercorrection in British English
noun: a mistaken correction to text or speech made through a desire to avoid nonstandard pronunciation or grammar