'Whacking' definitions:

Definition of 'whacking'

adverb

Extremely; "a whacking good story"

adjective

(British informal) enormous; "a whacking phone bill"; "a whacking lie"

noun

The act of inflicting corporal punishment with repeated blows [syn: beating, thrashing, licking, drubbing, lacing, trouncing, whacking]

From: GCIDE

Whack \Whack\, v. t. [imp. & p. p. Whacked; p. pr. & vb. n. Whacking.] [Cf. Thwack.]
1. To strike; to beat; to give a heavy or resounding blow to; to thrash; to make with whacks. [Colloq.] [1913 Webster]
Rodsmen were whackingtheir way through willow brakes. --G. W. Cable. [1913 Webster]
2. To divide into shares; as, to whack the spoils of a robbery; -- often with up. [Slang] [Webster 1913 Suppl.]

From: GCIDE