involutional vs knotty

of or pertaining to involution 

characterized by involution 

Of an austere or hard nature; rugged. 

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. 

Complicated or tricky; complex, difficult.