こんな時英語でどう言うの〜？英会話辞典 ：　

「や」

やあ〜　：　Oh !  Whoa !   Yikes !   Hello !   Hi there !   
やいやい言うな〜！　：　Don't pester me !   
八百長　：　Fixed (game).   Rigged (match).  
やがて　：　Soon.    Before long.   Almost.   
やかましい　：　Noisy.   Strict.   Fussy.   
焼きが回る　：　Lose one's edge (as one gets older).   Slow down.   
やきもき　：　Get upset.   
焼餅を焼く　：　Be jealous.   
焼きを入れる　：　Crack the whip.   Get tough on someone.   
役　：　Job.  Role.   
やくざ　：　Trash.   A mafioso.   A thug.   
約束　：　A promise.   An engagement.   
約束を守る人　：　A person who keeps a promise.   
役に立つ　：　Helpful.   Useful.   (Useless: 役立たない)　　
厄払い　：　Break the jinx.   Exorcise the demons.   Change one's luck.   
厄除け　：　A talisman.   A good-luck charm.    
やけになる　：　Give up hope.   Despair.   
やけに腹が立つ　：　I'm extremely irritated !   
やじ　：　Heckling.   Booing.   Jeering.    
やじうま　：　A voyeur.   A rubbernecker.   A curious mob.   
安上がり　：　Cheaper.   Economical.    
安い　：　Cheap.   Not too expensive.    
〜しやすい　：　Easy to ....    Apt to ...   　
安請け合い　：　Be too quick to promise.  Agree too quickly (to do something). 
安っぽい　：　Cheap-looking.   Tawdry.   
休まる　：　Feel relaxed.   Breathe easy.   
休む　：　Rest.   Go on break.   Be absent from.   Take (time) off.  
あの店は休みだ　：　That shop is closed.   
早く寝て、早く起きなさい　：　Early to bed and early to rise.  
僕たちは二時まで休む　：　We take a break until 2 pm.   
一日も休む事が出来ない　：　I can't even take one day off.    
安らぎを感じる　：　Feel peace of mind.    
やせ我慢　：　Grit one's teeth.   Bite the bullet.   Play the martyr.   
やせる　：　Lose weight.   
やたらに　：　Too much.   Too often.   Like there's no tomorrow.   
八つ当たり　：　Take it out on someone.   
厄介な問題　：　A complex problem.   A tangled situation.   
やっかいにならない　：　Can take care of oneself.    
やっかいになる　：　Be dependent on.   Stay with.    
厄介払い　：　Get rid of someone / something.   Put an end to something.  
やっき　：　Frantically.   
やった〜！　：　I did it !   
やったね〜！　：　You did it !   
やっつけ仕事　：　Careless work.   A half-assed job.   
やっつける　：　Let someone have it.   
やってのける　：　Take care of (the work, the matter, etc).  
やってみる　：　Give something a try.   
やってみるといいよ　：　It's worth a try.   
やってられないなあ　：　That burns me up !   That really gets to me !   
やっと　：　Just. (barely)      At last. (finally).   
やっとの思いで　：　Went through a lot (to achieve something).   
やっとわかったよ　：　Now I follow you.   
やっぱり!：　I knew it !      
やつら　：　(That) guy.   
やつれた　：　Look thin and tired.   Look wasted.   
やはり　：　Either.   As expected.   Of course.   Still.   
それもやはりだめです　：　That's no good either.  
彼はやはり失敗した　：　As expected, he failed.  
やぶ蛇　：　Backfire.   
破れかぶれ　：　Become desperate.    Lose it (mentally).   
やぼ　：　Stupid.   Lacks common sense.   
やましい　：　Feel guilty (about).   
やまやま　：　Very much. (We very much want to visit there, but we don't ..  
山をかける　：　Make a calculated guess.   Play a hunch.   
病み上がり　：　Until one gets better.   
病みつき　：　Addicted to.   Totally into.   
止むに止まれず： Forced to ..(because of circumstances beyond one's control)  
止むをえず　：　(Like it or not) Someone has to.  Have no choice but to.  
やめてよ！　：　Cut it out !   Stop it !   
やられる　：　Take a hit. (台風、病気等に)　　Was defeated.(ゲーム等に)　　
やりかけ　：　Work in progress.   
やりかねない　：　Be capable of.   Be liable to.   Just might.   
やりきる　：　Manage.  Juggle.   
やりきれない：　Never get it finished.  Can't stand something.（感情  　
やり過ぎ　：　Overdo.   Go too far.   
やり損なう　：　Fail.   
槍玉に挙げる：　Single someone out for (punishment, criticism, etc).   
やりっぱなしにする　：　Leave something unfinished.   
やり取り　：　Give and take.   Exchange (of ideas).  
やり直す　：　(Start) all over again.    Do again.   
やりにくい　：　Hard to do.   Difficult.   
やり場がない　：　Not know how to handle (one's anger, oneself).   
やる気　：　Drive.   Motivation.    
やれやれ　：　Man-oh-man !   Jeez !           

このコーナーは「講談社文庫」の「こんな時どう言う英会話辞典」（長村キット著）
から抜粋させて頂きました。
この本には役に立つフレーズが満載です。読み物としても面白いですよ〜！