/ɪnˈfekʃəs ||; ɪnˈfɛkʃəs/adj (used about a disease, illness, etc) that can be easily passed on to another person （指疾病等）传染的: Flu is very infectious. 流感极易传染。 (figurative 比喻) infectious laughter 很有感染力的笑声 Infectious diseases are usually passed on by the air that we breathe. Contagious diseases are passed from one person to another by touch. 通过呼吸传染的疾病叫做infectious diseases﹐通过接触传染的疾病则叫做contagious diseases。