Definition - resistance or opposition in response to a policy or regulation especially by those affected
Pushback is today often found used in a figurative manner, with no physical objects being pushed.
A social moderate, Mr. Pataki signed a gay rights bill while in office, is in favor of abortion rights and passed a tough gun-control law that received pushback from conservatives.
— Heather Haddon, The Wall Street Journal, 23 Apr. 2015
In the 1930s the word was often found applied to a new type of seat found in movie theaters.
Hopkins … Theatre of Luxurious Comfort With Swanky Push-Back Seats
— (advt.) Oakland Tribune, 18 Nov. 1939
It was the plan of Harry Greenman, manager, to allow the patrons to seat themselves in the new “push-back” seats for the first time in the dark.
— St. Louis Globe-Democrat, 9 Nov. 1939
Much of the early use of pushback as a noun comes during the Second World War, in reference to the pushing back of troops.
What actually has happened is that the Reds achieved a push-back of the Finnish front line of resistance and not a break-through.
— The Des Moines Register (Des Moines, IA), 7 Mar. 1940
Whatever he does, the Russian push-back is of immense help to the western democracies in western, middle and far eastern areas.
— Democrat and Chronicle (Rochester, NY), 16 Dec. 1941