Wiktionary
vb. (context archaic English) Third-person singular present simple form of '''deal'''
Usage examples of "dealeth".
Artegall dealeth right betwixttwo brethren that doe strive,Saues Terpine from the gallow tree,and doth from death repriue.
So within a while Sir Kay came riding that way, and then Sir Gaheris took his horse and met him, and said: Sir Kay, ye are not wise to ride at the request of King Mark, for he dealeth all with treason.
One also hath made a book of the spider and the fly, wherein he dealeth so profoundly, and beyond all measure of skill that neither he himself that made it nor any one that readeth it can reach unto the meaning thereof.
He that dealeth in the produce of the beaver must have the animal’s perseverance and forethought!
Give most hearty thanks to the Supreme Goodness, who dealeth with thee so graciously, visiteth thee so lovingly, stirreth thee up so fervently, raiseth thee so powerfully, lest thou sink down through thine own weight, to earthly things.