Originally started as marijuana slang, it referred to weed that looked like the mack daddy, but was actually only middies. So the "pretendica" has now become generally thus, something that looks great, but is actually only okay, so-so, average at best.
something that has the capacity of pretending or is in the act of pretending or faking it.
pretending, faking, fronting.
The girl thought that she had a hot ride, but it was total pretendica.
"Was it the shit, man?" -"Naw, it was pretendica."
"It was some scenester shit, yo. Total pretendica."