/ɪnˈfɔ:ml ||; ɪnˈfɔrmḷ/adj relaxed and friendly or suitable for a relaxed occasion 轻松友好的；不拘礼节的；非正式的: Don't get dressed up for the party -- it'll be very informal. 这个酒会十分不拘形式，用不着盛装出席。The two leaders had informal discussions before the conference began. 两位领袖在会议之前进行过非正式的讨论。 [OPP] formal 反义词为formal ☞Some words and expressions in this dictionary are described as (informal). This means that you can use them when you are speaking to friends or people that you know well but that you should not use them in written work, official letters, etc. 本词典里有些词语、词组都有（informal非正式）这标示，表示这些词语可在跟熟人讲话时使用，书面语或正式信件则不宜用。 ➔informality /ˌɪnfɔ:ˈmæləti ||; ˌɪnfɔrˈmælətɪ/ noun [U]: an atmosphere of informality 轻松的气氛 ➔informally /-məli/ adv I was told informally (= unofficially) that our plans had been accepted. 我接到非正式的通知，我们的计划已经通过了。