Seddity – is defined as an African American who is bourgeois, snobbish or pretentious. According to Lisa J. Green’s study of the African American lexicon

Lexicon

In linguistics, the lexicon of a language is its vocabulary, including its words and expressions. A lexicon is also a synonym of the word thesaurus. More formally, it is a language's inventory of lexemes. Coined in English 1603, the word "lexicon" derives from the Greek "λεξικόν" , neut...

 in African American English: a linguistic introduction, the usage of the word spanned from 1960 – 1980.

As to the disparity in the spelling, this is attributed to certain lexical items being predominantly of oral context as opposed to spelling conventions in AAVE African American Vernacular English

African American Vernacular English

African American Vernacular English —also called African American English; less precisely Black English, Black Vernacular, Black English Vernacular , or Black Vernacular English —is an African American variety of American English...

.

Also, as part of AAVE, seddity/saddity/siditty is deemed as a people termRickford http://www.phbern.ch/fileadmin/CAMPUS/06_IS1/Englisch/Dokumente/Spoken_Soul.doc like words such as cuz and posse.

See also

• Bourgeois
• Lexicon
  Lexicon
  In linguistics, the lexicon of a language is its vocabulary, including its words and expressions. A lexicon is also a synonym of the word thesaurus. More formally, it is a language's inventory of lexemes. Coined in English 1603, the word "lexicon" derives from the Greek "λεξικόν" , neut...
  
  
• African American Vernacular English
  African American Vernacular English
  African American Vernacular English —also called African American English; less precisely Black English, Black Vernacular, Black English Vernacular , or Black Vernacular English —is an African American variety of American English...
  
  
• Creole language
  Creole language
  A creole language, or simply a creole, is a stable natural language developed from the mixing of parent languages; creoles differ from pidgins in that they have been nativized by children as their primary language, making them have features of natural languages that are normally missing from...
  
  
• Slang
  Slang
  Slang is the use of informal words and expressions that are not considered standard in the speaker's language or dialect but are considered more acceptable when used socially. Slang is often to be found in areas of the lexicon that refer to things considered taboo...