חִנָּם

From LSJ

ψυχῶν σοφῶν φροντιστήριονthought-shop of wise souls

Source

English (Strong)

from חֵן; gratis, i.e. devoid of cost, reason or advantage: without a cause (cost, wages), causeless, to cost nothing, free(-ly), innocent, for nothing (nought, in vain.