Know why cattywampus was trending last week?
1880, noun and verb, from Irish Land League ostracism of Capt. Charles C. Boycott (1832-1897), land agent of Lough-Mask in County Mayo, who refused to lower rents for his tenant farmers. Quickly adopted by newspapers in languages as far afield as Japanese (boikotto). The family name is from a place in England.
The refusal to purchase the products of an individual, corporation, or nation as a way to bring social and political pressure for change.