Английские идиомы сравнения образуются при помощи союзов/предлогов AS или LIKE. В большинстве случае случаев идиомы образуются по паттерну AS + прилагательное + AS + существительное. Первый союз AS в идиоме чаще всего опускается.

Примеры идиом сравнения с союзом AS

As blind as a bat (unable to see well) - совершенно слепой (слепой как летучая мышь, как крот)

As bald as a coot (completely bald) - совершенно лысый 

As brown as a berry (entirely or very brown; often referring to a suntanned skin) - совершенно коричневый, очень загорелый

As busy as a bee (to be moving about quickly doing many things)  - очень занятый

As cold as a fish (unemotional) - холодный, неэмоциональный

As cold as a stone/ice (very cold) - холодный как камень (как лед)

As clean as a whistle (extremely clean) - очень чистый

As clear as mud (ironic, meaning not clear at all; very difficult to understand) - ирония: совсем не ясно/дело ясное, что дело темное

As cool as a cucumber (very calm or very calmly, especially when this is surprising) - невозмутимо спокойный

As dead as a doornail (dead, devoid of life, unusable) - мертвый, погибший, лишенный жизни

As delicate as a flower (fragile) - хрупкий, как цветок

As easy as ABC (very simple) - очень просто, просто как дважды два, пара пустяков

As easy as pie (very easy) - очень просто, просто как дважды два, пара пустяков

As fit as a butcher's dog (very fit and healthy) - в прекрасном здоровье, состоянии и настроении

As fit as a fiddle (very healthy) -  в прекрасном здоровье, состоянии и настроении

As flat as a pancake (very flat and level) - совершенно плоский, плоский как доска

As free as a bird (free to go anywhere) - вольный как птица

As fresh as a daisy (clean and fresh/ to be full of energy and enthusiasm) - цветущий/бодрый/энергичный

As gentle as a lamb (very gentle) - кроткий как ягненок

As happy as a dog with two tails (very happy) - радостный, счастливый, жизнерадостный

As happy as Larry (very happy) - радостный, счастливый, жизнерадостный

As happy as a sandboy (very happy and content) - радостный, счастливый, жизнерадостный, довольный

As hard/tough as nails (a person who is very tough, strong and very determined) - твердый как кремень, жесткий

As helpless as a baby (absolutely helpless) - беспомощный как младенец

As keen as mustard (very enthusiastic) - горящий желанием, полный энтузиазма

As good as gold (very good/ (of a child) to behave very well) - золотой характер (особенно о детях)

As light as a feather (light in weight) - легкий как перышко

As mad as a March hare (extremely silly or stupid)  - безумный как мартовский заяц

As mad as a wet hen (completely mad) - безумный, сумасшедший

As nice as ninepence (neat, tidy, well-ordered) - чистый, хорошо организованный

As old as Methuselah (very old) - очень старый

As old as the hills (exceedingly old) - древний, старо как мир

As plain as day (clear to see) - ясно как белый день, совершенно очевидно

As plain as the nose on your face (to be very obvious) - совершенно очевидно

As pleased as Punch (very pleased) - довольный как слон

As poor as a church mouse (extremely poor) - бедный как церковный мышь

As proud as a peacock (very proud) - гордый как павлин

As pure as driven snow (entirely pure, innocent/ to be morally completely good) - белоснежный

As quiet as a mouse (very quiet) - тихий как мышь

As quick as a wink (happens in a short amount of time) - в мгновение ока, молниеносный

As rare as hens' teeth (extremely rare) - очень редкий

As red as a beetroot (to have a red face because you are embarrassed) - покраснеть как свекла

As regular as clockwork (never late or always at the same time) - работать как часы, регулярный

As right as rain (to feel healthy or well again) - в полном порядке, в добром здравии

As safe as the Bank of England (strong and secure) - очень надежный и безопасный

As sick as a dog (very sick /vomiting a lot) - очень больной

As silent as the grave (to say absolutely nothing) - молчать как могила

As silly as a goose (very foolish) - глупый как пробка

As slow as molasses (moves very slowly) - медленный

As slippery as a fish (a person who is not trustworthy) - "скользкий человек"

As slippery as an eel (a person who is not trustworthy) - "скользкий человек"

As sly as a fox (a person who is clever and tricky) - хитрый как лиса

As small as the hairs on a gnat's bullock (tiny, very small) - крошечный

As smooth as silk (very smooth) - гладкий как шелк

As smooth as a baby's bottom (extremely smooth) - гладкий как попка младенца

As snug as a bug in a rug (comfortable and warm) - уютный и комфортный

As sober as a judge (to not be at all drunk) - трезвый, серьезный

As sound as a bell (to be very healthy or in very good condition) - очень здоровый

As straight as an arrow (very straight) - прямой как стрела

As strong as an ox (very strong) - сильный как бык

As stubborn as a mule (very obstinate) - упрямый как осел

As sturdy as an oak tree (very strong) - сильный как дуб

As sweet as honey (very sweet) - сладкий как мед

As tall as a tree (very tall) - очень высокий

As thick as a brick (not very smart) - тупой, глупый

As ugly as sin (very guilty, miserable, or ugly) - безобразный

As white as a ghost (pure white) - белый как приведение

As white as snow (pure white) - белый как снег

As wise as an owl (very wise) - мудрый как сова