Straight Cheeks refers to the level of skill someone has at something which is inferior to most. You may also hear someone refer to such pisspoor skill-level as, "straight buns"
Yo, Mike is straight cheeks at 2K! He can't even guard with his defender!
A thoinkster is a dismissive name for a goofy female.
Thoinkster may also mean "hoe" or "thot" if used in the right context.
"Don't come for me, you thoinkster"