Hair

/ˈher/

[back-formation from hairy]

n. The complications that make something hairy.

"Decoding TECO commands requires a certain amount of hair."

Often seen in the phrase 'infinite hair', which connotes extreme complexity. Also in 'hairiferous' (tending to promote hair growth):

"GNUMACS Elisp encourages lusers to write complex editing modes."

"Yeah, it's pretty hairiferous all right." (or just: "Hair squared!")