Uptight in an utterly conceited sort of
way.
Someone who 'acts' as if they are completely superior towards/around another
person.
Someone who's of the perception that they are '
better' (physically and mentally) than another.
"Me and
Jen went to Saks the other
day, she's a completely different person over there, actin all sadiddy"
"Yo, if you wanna roll and chill tonight we can do it, but
don't try to be actin' all sadiddy around my homies"
"I am not goin' to the club with HIM","Stop bein sadiddy and lez' go."