againstism
/əˈɡɛnstɪz(ə)m/ /əˈɡeɪnstɪz(ə)m/informal (originally US )
noun
The position or practice of being opposed to something, or of having an oppositional attitude in general; (habitual) opposition or criticism.
Origin
1940s. From against + -ism. Compare earlier againstness, againster.