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."
A female that is really a hoe but tries to actas if she is not. She is a high class hoe.
Boy 1: After the club I tried to take her to Motel Six..
Boy 2: How did that work out?
Boy 1: It didn't.. she wanted to go to the Hilton Hotel
Boy 2: Hell naw! She a siddidy hoe!
yall gotta learn yo shit. sadiddy comes from sadistic. Sadiddy is a softer way to say it. Like beezy is to bitch. Sadistic means extremely cruel, so sadiddy means cruel or mean. Being conceited is only one way to be sadiddy. If yo chick is messin round behind yo back, thats some sadiddy shit. Dudes, tellin a chick you gonna call her after she gives you her digits and never callin, thats sadiddy.
"tonight its gon' be some changes, no acting sadiddy, so stop acting and get it clapping cause i'm knowing you feel me" -Baby Huey
"Girl why you actin all sadiddy in the club, telling yo chicks you dont know me?"
"No way girl, you dont wanna go for that dude, he all sadiddy, droppin chicks faster than stacks"