dead set against

Unutterably   opposed.  This  Americanism   probably comes from industry, where a machine is said to be dead set when it is fas- tened  so  that  it  cannot  be  made  to  move. The  transfer  to  firm  resolve  or hostility against some person, course of action, and so on, was made by the early  nineteenth  century. “A  dead  set  is  to  be  made  from  various  quarters against  the  abominable  innovation  of  publishing  Divisions  by  authority”

(General P. Thompson, 1836).