Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
Of Jordan (Jer. 12:5), literally the "pride" of Jordan (as in R.V.), i.e., the luxuriant thickets of tamarisks, poplars, reeds, etc., which were the lair of lions and other beasts of prey. The reference is not to the overflowing of the river banks. (Comp. 49:19, 50:44; Zech. 11:3).