upsetter

noun

up·​set·​ter

ˌəpˈsetə(r)

plural -s

: one that upsets: such as

a

: a person who causes upsets

the businessman … is the great upsetter on the contemporary scene

—M. S. Rukeyser

b

: an upsetting machine

c

: a forging press operator who increases the breadth of a piece of metal by heating and pressing it so that it spreads

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