Adjective

(en-adj)

Urgent.

Sensitive.

Short, quick, brief.

* {{quote-magazine, year=2013, month=July-August, author= Philip J. Bushnell

, title= Solvents, Ethanol, Car Crashes & Tolerance, magazine=(American Scientist) , passage=Surprisingly, this analysis revealed that acute exposure to solvent vapors at concentrations below those associated with long-term effects appears to increase the risk of a fatal automobile accident. Furthermore, this increase in risk is comparable to the risk of death from leukemia after long-term exposure to benzene, another solvent, which has the well-known property of causing this type of cancer.}}

(geometry) Of an angle, less than 90 degrees.

(geometry) Of a triangle, having all three interior angles measuring less than 90 degrees.

(botany, of leaves) With the sides meeting directly to form a pointed acute angle at the apex, base, or both.

(medicine) Of an abnormal condition of recent or sudden onset, in contrast to delayed onset; this sense does not imply severity (unlike the common usage).

(medicine) Of a short-lived condition, in contrast to a chronic condition; this sense also does not imply severity.

* {{quote-magazine, year=2013, month=May-June, author= Katie L. Burke

, title= In the News , volume=101, issue=3, page=193, magazine=(American Scientist) , passage=Bats host many high-profile viruses that can infect humans, including severe acute respiratory syndrome and Ebola. A recent study explored the ecological variables that may contribute to bats’ propensity to harbor such zoonotic diseases by comparing them with another order of common reservoir hosts: rodents.}}

(orthography, after a letter) Having an acute accent.

High or shrill.

an acute tone or accent

Adjective

(en adjective)

Opposed to change; urging a return to a previous state.

Very conservative.

* {{quote-book

, date = 2011-09-29 , title = The Reactionary Mind: Conservatism from Edmund Burke to Sarah Palin , author = Corey Robin , location = New York , publisher = Oxford University Press , isbn = 9780199793747 , ol = 25101368M , page = 25 , pageurl = http://books.google.com/books?id=CWxIz_Gm9WMC&pg=PA25&dq=reactionary , passage = 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. }}

(chemistry) Of, pertaining to, participating in or inducing a chemical reaction.

* 2013 , Brandon Smith, Are Individuals The Property Of The Collective?

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.