Reaction

(chemistry) a process in which one or more substances are changed into others

an idea evoked by some experience

a bodily process occurring due to the effect of some antecedent stimulus or agent

(mechanics) the equal and opposite force that is produced when any force is applied to a body

a response that reveals a person's feelings or attitude

extreme conservatism in political or social matters

doing something in opposition to another way of doing it that you don't like