mindmap root((减缓)) delay implies a holding back, usually by interference, from completion or arrival: bad weather ~ed our return. retard applies chiefly to motion and suggests a slowing, often by interference: language barriers ~ed their rate of learning. slow often used with up or down, also implies a reduction of speed, often with deliberate intention: the engineer ~ed the train. slacken suggests an easing up or relaxing of power or effort: he needs to ~ his pace if he intends to finish the race. detain implies a holding back beyond a reasonable or appointed time, often with resulting delay: unexpected business had ~ed her.