v. t.
Rodsmen were whackingtheir way through willow brakes. G. W. Cable. [ 1913 Webster ]
v. i. To strike anything with a smart blow. [ 1913 Webster ]
To whack away,
n.
Out of whack,
n. [ 1913 Webster ]
a. Very large; whapping. [ Colloq. ] [ 1913 Webster ]
v. t. to sever with a blow; to cut off. [ PJC ]
v. i. to masturbate. [ Vulgar ] [ PJC ]