A combination of "skinny" and "attitude"; the loud, boisterous, obnoxious arrogance often displayed by skinny "beautiful people" with low to no intelligence and/or small sexual attributes such as breasts or penises'. This is very common; many thin people often try to compensate for their insecurity with their mental and/or sexual triviality by loudly and cruelly berating "overweight" people.
"oh no he didn't just say that, that skinny ass moron on this talk show better just get over his tiny penis and own up to his skinnitude"
Subbitude is a word describing sub standard attitudes that some people demonstrate as part of their personality. It is a negative attitude, bordering on aggressiveness and disregard for other peoples value as human beings. It can be demonstrated by all 3 genders; males, females and gays are equally likely to have this attitude.
"Misogynist has only been here for three months and already there's a noticeable change in attitude - sub-standard attitudes and spitefulness are spreading - 'subbitudes' are taking over."
Extract from "Misogynist" in "Stories that shock" by Tianne Waters.