subs. and verb. (B. E. and GROSE).To Beat with a Stick or Cudgel (B. E.); a great blow with a stick across the shoulders (GROSE); THICK-THWACK = blow after blow.
1575. R[ICHARD] B[OWER], Appius and Virginia [DODSLEY, Old Plays (HAZLITT), iv. 123]. With THWICK THWACK, with thump thump.
d. 1618. STANYHURST, Conceites [ARBER], 138. With peale meale ramping, with THWICK THWACK sturdelye thundring.