Green’s Dictionary of Slang

1. a blow.

1693

Proc. Old Bailey 31 May n.p.: He took his Cane, and gave her two or three good daubs (as he called them);.

2. a bribe.

1725		New Canting Dict. n.p.: dawb a Bribe; a Reward for secret Service; as, The Cull was gybbed, because he could not dawb. The Rogue was punished, because he had no Pence to bribe off his Sentence.
1737, 1759, 1760, 1776		Bailey Universal Etym. Eng. Dict. [as cit. 1725].
c.1750–1882		B.M. Carew Life and Adventures.

3. a spot of grease used to mark a card.

1963

A.S. Fleischman Venetian Blonde (2006) 155: I watched for daub. He could be grease-marking the high cards every time he smoothed his moustache.