A blow. This is better than a thump on the back with a stone; said on giving any one a drink of good liquor on a cold morning. Thatch, thistle, thunder, and thump; words to the Irish, like the Shibboleth of the Hebrews.
Definition taken from The 1811 Dictionary of the Vulgar Tongue, originally by Francis Grose.
Thcmmikins * ThumpingNathan Bailey's 1736 Dictionary of canting and thieving slang
John S. Farmer's collection of canting songs and slang rhymes