Withal, adv.
Etymology: [With + all.]
1. With this; with that. [Obs.] He will scarce be pleased withal. Shak.
2. Together with this; likewise; at the same time; in addition; also. [Archaic] Fy on possession But if a man be virtuous withal. Chaucer. If you choose that, then I am yours withal. Shak. How modest in exception, and withal How terrible in constant resolution. Shak.
1 other Webster entry under this spelling
Withal, prep.
With; -- put after its object, at the end of sentence or clause in which it stands. [Obs.] This diamond he greets your wife withal. Shak. Whatsoever uncleanness it be that a man shall be defiled withal. Lev. v. 3.
Shades of meaning
Fernald has no entry of its own for withal; he lists it under also.
Where he writes about it:
The words fall into two groups; as well as, besides, in addition, too, withal, simply add a fact or thought; also (all so), in like manner, likewise, similarly, affirm that what is added is like that to which it is added. — from also