reactionary

adjective more reactionary · most reactionary

1. Extremely conservative; opposing revolution (such as the French Revolution); favoring a return to a "golden age" of the past. There's a fairly simple reason for the embrace of radicalism on the right, and it has to do with the reactionary imperative that lies at the core of conservative doctrine. […] If he is to preserve what he values, the conservative must declare war against the culture as it is.

   Similar: antiprogressive, regressive · Opposite: progressive, nonreactionary

2. Of, pertaining to, participating in, or inducing a chemical reaction. Psychiatry extends the theory into biology in the belief that all human behavior is nothing more than a series of reactionary chemical processes in the brain that determine pre-coded genetic responses built up from the conditioning of one’s environment.
3. In reaction to; as a result of. The regulator noted that reduced service levels and passenger numbers helped deliver strong performance, with fewer reactionary delays.

noun reactionaries

1. One who opposes revolution, wanting to reverse it, favoring a return to a past golden age, often used derogatorily by revolutionaires. Hindu reactionaries, whose conception of a well-ordered society had not moved beyond the laws of Manu, fell into line for the moment with the intellectual products of the modern Indian University.

   Similar: antiprogressive

Opposite: progressive