Word Study
ain't
CIDE DICTIONARY
ain't,
A contraction for are not and am not; also used for is not. [Colloq. or illiterate speech]. See An't. [1913 Webster]
OXFORD DICTIONARY
ain't, contr. colloq.
1 am not; are not; is not (you ain't doing it right; she ain't nice).
2 has not; have not (we ain't seen him).
1 am not; are not; is not (you ain't doing it right; she ain't nice).
2 has not; have not (we ain't seen him).
Usage
Usually regarded as an uneducated use, and unacceptable in spoken and written English, except to represent dialect speech.
Etymology
contr. of are not
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