colloq. [f. WHACK(ER + -ING2.] That is a whacker; abnormally large; thumping, whopping.
Often quasi-advb. in whacking big, great.
1823. Scott, Quentin D., Introd. 77. A certain whacking priest in our neighbourhood. Ibid. (1829), Jrnl., 16 April (1890), II. 268. This whacking reason.
1853. G. J. Cayley, Las Alforjas, II. 193. We saw a whacking great building.
1873. C. M. Davies, Unorth. Lond., Walworth Jumpers, 91. A good whacking kiss that echoed all over the archway.