ATTEMPT [C, U] › an attempt to do something: [+ to do sth] We huddled together in an effort to keep warm. He was making an effort to be sociable. ENERGY [U] › the energy that you need to do something: I put a lot of effort into organizing the party. [+ to do sth] It would take too much effort to tidy my bedroom. › [U] the force that is used to make something move be an effort › to be difficult or painful: After his accident, walking was an effort.