Gnarled, knotty, twisted.
To knot or twist something.
To snarl or growl; to gnar.
A knot in wood; a large or hard knot, or a protuberance with twisted grain, on a tree.
Something resembling a knot in wood, such as in stone or limbs.
active, vigorous and rough, with the possibility of harm
highly competitive
Engage in rough-and-tumble activity
An environment of rough activity
Rough activity; fighting or brawling; a fight.
A person who characteristically engages in such activity