(adj): characterized by or full of force and vigor
(adj): markedly effective as if by emotional pressure
(adj): producing a strong effect
(adj): crude but effective for the purpose at hand
(adj): able to accomplish a purpose; functioning effectively
(adj): vs. incompetent) -- (properly or sufficiently qualified or capable or efficient
(adj): works well as a means or remedy
(adj): vs. inefficacious) -- (marked by qualities giving the power to produce an intended effect
(adj): predicate), in force(predicate) -- (exerting force or influence
(adj): vs. inoperative) -- (being in force or having or exerting force
(adj): existing in fact; not theoretical; real
(adj): vs. potential), existent -- (presently existing in fact and not merely potential or possible
(adj): ready for service
(adj): vs. nonoperational) -- ((military) of or intended for or involved in military operations
"If, as some environmentalists demand, it is to happen worldwide, then much of the arable surface of the planet will be deployed to produce food for cars, not people. The market responds to money, not need. People who own cars - by definition - have more money than people at risk of starvation: their demand is effective, while the groans of people at risk of the starving are not. In a contest between cars and people, the cars would win. Something rather like this is happening already. Though 800 million people are permanently malnourished, the global increase in crop production is being used mostly to feed animals: the number of livestock on earth has quintupled since 1950. The reason is that those who buy meat and dairy products have more purchasing power than those who buy only subsistence crops."
- 'Heat', George Monbiot.