If you are wanting to say you had a 'not very nice' or 'unpleasant' dream then it is called a 'nightmare' or a 'bad dream' so you would say 'I had a nightmare/bad dream last night'
悪い夢は'nightmare'や'bad dream'といいます。
例えば：
'I had a nightmare/bad dream last night'
（昨日の夜、悪夢／悪い夢を見ました）
A bad dream can also be called:
A nightmare.
A night terror.
My daughter suffers from night terrors.
My favourite horror movie is A Nightmare On Elm Street.
bad dream'（悪夢）は次のように言うこともできます。
A nightmare = 悪夢
A night terror = 夜驚症
My daughter suffers from night terrors.（娘が夜驚症にかかっています）
My favourite horror movie is A Nightmare On Elm Street.（私の好きなホラー映画は「エルム街の悪夢」です）
Last night I had the most awful dream or
Last night I had the most awful nightmare.
This is often said to someone if you are relaying a
nightmare that left you feeling anxious and afraid.
I had an unpleasant dream last night.
An unpleasant dream is also one in which you wake up
still feeling very tense and unsettled.
Last night I had the most awful dream（昨日の夜、すごく恐ろしい夢を見た）
または、
Last night I had the most awful nightmare（昨日の夜、すごく恐ろしい夢を見た）
これは、悪夢について話すときによく使われます。
I had an unpleasant dream last night（昨日の夜、嫌な夢を見た）
'unpleasant dream'（嫌な夢）も、目が覚めてもまだ不安を感じるような夢を言います。
こんにちは。
「悪夢」は英語で nightmare と言えます。
他には「悪い夢」という意味の bad dream もあります。
下記は例文ですのでぜひ参考にしてください。
I woke up from a bad dream in the middle of the night.
「真夜中に、悪い夢から目覚めた」
I had a nightmare last night.
「昨晩は悪夢をみた」
ぜひ参考にしてください。
「悪夢」という言葉を英語で伝えると、「bad dream」という表現と「nightmare」という言葉を使っても良いです。「Bad」は「悪い」という意味があって、「dream」は「夢」という意味があります。例えば、「I had a bad dream.」と「I had a nightmare.」と言っても良いです。この場合、「had」は「夢を見た」という意味があります。「Dream」という動詞も使っても良いと考えました。
I had a very bad dream last night. I'm still scared whenever I think about it.
Whenever I watch a horror movie, I have nightmares all night long.
I had a nightmare where ghosts were walking around my bed.
悪夢 nightmare, bad dream
昨夜はとても悪い夢を見ました。 それについて考えるときはいつでも私はまだ怖いです。
I had a very bad dream last night. I'm still scared whenever I think about it.
私がホラー映画を見るときはいつでも、一晩中悪夢を見ています。
Whenever I watch a horror movie, I have nightmares all night long.
私は幽霊が私のベッドの周りを歩いている悪夢を見ました。
I had a nightmare where ghosts were walking around my bed.
Well, either of the above expressions are pretty normal. however, quite often. especially in a more formal situation, people do not actually like to describe the details of their sleep - it is quite private information, after all. People would be more likely to say something like: 'I didn't sleep well last night.' or, 'I had trouble sleeping' ..... or possibly, 'I couldn't get to sleep last night.' Another well-known phrase is: 'I hardly slept a wink last night' - meaning, (for some reason) you had hardly any sleep.
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