siditty etymology? BE for feeling superior(1967)

[Douglas G. Wilson]

>Unfortunately, though I'm quite familiar with this term, I can't hazard
>even a WAG as to its origin or even as to its "correct" spelling. It's
>what I call a "traditional" term: a term that was in use when my
>parents were teens. I heard it in the house before I heard it on the
>street. For what little it's worth, I do agree that the pronunciation
>indicated by Ms. Angelou's spelling, i.e. that the vowel of the first
>syllable is [I] and not [i]. [E], or schwa, is the "correct" one.

What about the stress? DARE has pronunciations all over the place, but only
from 1967 or so.

How did this word sound in earlier days? Did it have first-syllable stress
(rhyming with "avidity" maybe)? Or did it have second-syllable stress
(rhyming with "kitty") as it would appear to in some lyrics on the Web?
[DARE shows both.]

-- Doug Wilson