It's description of a kid appearence from the same book:
"He had a tuff of blond hair over his left eye, and a cascade of hair over the collar of his shirt. His blue eyes were as bright as marbles, and he seemed constantly grinning."
None of the "tuff" definitions I've found related to hair. Thank you for your help.
(I can hardly imagine "blue eyes as bright as marbles" as well).