I was researching "siddity" because one of my students used it in a paper. I have never heard this term before (I am a child of the 60s). My student is black and about 18.

Her cousin accused her of living in an area full of "siddity" and that she was "acting white." He ended up in jail, while she is in college. :) She said she did not know what "siddity" meant.