Where does the word 'reactionary' come from?

Question

I am interested in the origin of this word, strictly in the political usage of the word (Reactionary = conservative, right-wing). The definition is simple enough:

Reactionary: Characterized by reaction, especially opposition to progress or liberalism; extremely conservative.

This seems to be a designation of someone who is opposed to political revolution. Is this word more of an insult than a descriptive term?

"Oh they are just a reactionary... no original ideas, just reacting to the idea of progress."

What I am really interested in why the right-wing of politics are called 'Reactionaries'. Surely both sides of politics are reacting to social/political/religious structure/movements? To me, the word conservative is a better fit.

Answer 1

The term of French origin appears to have been first used in the current sense by mid-19th century in Marxist use:

Reactionary:

1831, on model of French réactionnaire (19c.), from réaction (see reaction). In Marxist use, "tending toward reversing existing tendencies," opposed to revolutionary and used opprobriously in reference to opponents of communism, by 1858. As a noun, "person considered reactionary," especially in politics, one who seeks to check or undo political action, by 1855.

(Etymonline)