An April Fool is defined as: "One who issportivelyimposed upon by others on the first day of April."

 Let's look and see what the Bible says

"Speak not in the ears of a fool: for he will despise the wisdom of thy words."
~Proverbs 23:9~

"For a dream cometh through the multitude of business; and a fool's voice [is known] by multitude of words."
~Ecclesiastes 5:3~

 Let's look and see what the celebrities say

"The first of April, some do say, Is set apart for All Fools' Day. But why the people call it so, Nor I, nor they themselves do know. But on this day are people sent On purpose for pure merriment."
~Poor Robin's Almanac(1790)~

"The first of April is the day we remember what we are the other 364 days of the year."
~By Mark Twain~

  Remember these words on April Fool's day

April 1st can be filled with 'giggles and smiles', it is okay to have fun...
but don't do things to "hurt" other people. Treat others as you would want them to treat you...now go and have a bit of harmless fun."

 Let's learn some words and expressions

1〉關于fool

Fool: one who counterfeits folly; a professional jester or buffoon in dramas （我們常見的fool即“傻瓜”，但如果讀莎士比亞的戲劇如King Lear《李爾王》，你會發現國王身旁常常有一個"Fool"。這時可要記住哦，Fool在這里可不是傻子而是絕頂聰明的“宮廷小丑”，他拿自身的滑稽或外顯的愚蠢和瘋癲作為護身符，說出一般人不敢或不愿說出來的真話。）

play the fool/act the foll: to act like the idiot or foolishly（胡鬧，辦傻事）

fool around:to spend time doing nothing useful（虛度光陰，游手好閑）

Fool's haste is no spead: 欲速則不達

make an April fool of sb: 把某人當作愚人節惡作劇的對象

fool's erand: a fruitless mission or undertaking（徒勞無用的工作）

fool's paradise:happiness founded on a illusion（虛幻的美夢，不可實現的希望）

2〉關于“玩笑，騙局”的表達

hoax: an attempt to trick an audience into believing that something false is real;an outrageous claim that is publicly exposed as a lie or deception（根據英文釋義，漢語中的“騙局”與hoax很貼切，常常指公眾群體受到愚弄。在西方，媒體往往在愚人節這天制造一些出格的hoax給公眾開玩笑）。

例句：I hoaxed you into believing that the mouse has eaten the cat（我騙你相信老鼠吃了貓）。

prank: a mischievous trick（惡作劇，與hoax相比，prank更側重于朋友之間或熟人之間的玩笑或惡作劇。搞惡作劇的人常常被稱作prankster）

例句：He likes playing pranks on the fellows around（他喜歡搞些惡作劇給周圍的人）。

practical joke: 與“verbal joke”（耍嘴皮開玩笑）相對應，practical joke更側重于行動。當然，既然已有古訓“Action speaks louder than words”，那么practical joke一定不是小兒科式的低級玩笑，它需要搞惡作劇的人多費些心思，使玩笑更高明一點。

例句：The first day of April is devoted to practical jokes（人們喜歡在愚人節開玩笑）。

3〉關于“魚”

feel like a fish out of water: 猶如魚而離水，感到生疏，不能適應環境

drink like a fish: 酗酒, 牛飲

All is fish that comes to his net: 來者不拒

Never offer to teach fish to swim: 不要班門弄斧

The best fish swim near the bottom: 珍貴的東西不能輕易得到

Never fry a fish till it's caught: 不要操之過急

April fish: 愚人節被愚弄的人，法國人愚弄他們朋友的方式就是在朋友的背后貼上一條紙做的魚，當有人發現這個惡作劇時，他們就會大笑著喊:“Poisson d'Avril”（四月魚）！這一說法緣于四月份的魚剛剛孵化出來，很容易上鉤被捉。

(英語點津陳蓓編輯）

sportively: playfully,given to merry trickery（在句中與imposed連用，表示“被某人捉弄”）

Poor Robin's Almanac: 《可憐的理查歷書》，為本杰明·富蘭克林所著