Intricate, involved, entangled, complicated, complex.
A genealogical coefficient of a given genealogical tree; defined as the difference between the number of theoretical ancestors of a person and the number of his/her real ones in a given generation (the degree of pedigree collapse).
Complicated or tricky; complex, difficult.
Of a part of the body, a tree, etc.: full of knots (knobs or swellings); gnarled, knobbly.
Of string or something stringlike: full of, or tied up, in knots.
Of an austere or hard nature; rugged.