A some what vintage term used widely amongst the older men to rate woman. If a man and his buddies saw an attractive woman walk by they'd rate her from 1-40. 40 being a sheem - or thirty-eight-two. Therefore a sheem is a fine woman, top-notch, dime-piece... the dream woman, especially in the physical sense.
Daniel: Did you see Shelia? Damn!
Tom: Hells yea, shes fourty fasho - she's a sheem.
A turd that has been flattened slightly by the pressure of a toddler's booty on his or her undies or diaper. Essentially, a sheem is a poop that has been executed covertly and then squished. Usually there is some reluctance on the part of the sheemer to acknowledge that he's carrying a load, probably because he's in the midst of potty training and doesn't want to get with the program.
Today (says my three-year-old son about another kid at daycare), Brady had a sheem in his pants and it was in his diaper because he doesn't go on the potty!
Sheems is legit. Sheems is someone you want to be friends with because she will always have your back. She is smart in school and has high goals for herself, she wont be let donw in life. She makes you feel better no matter what and i love her.