[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!")