いろんな言い方ができると思いますがいくつかピックアップしました。
I'll go in my everyday clothes.
普段着のまま[行く](https://eikaiwa.dmm.com/uknow/questions/75832/)つもり。
This is what I normally wear.
[普段は](https://eikaiwa.dmm.com/uknow/questions/84158/)こんな格好だよ。（これが私の普段着だよ。）
普段着は、
everyday clothes でOKですが、
「普段着でお越しください」という場合の普段着は
casual wear/clothes といいます。
(wear は、お店などで売られている衣料品の種類のまとめた言い方・clothes は個人が着ているもの）
「[正装](https://eikaiwa.dmm.com/uknow/questions/71126/)は[必要ない](https://eikaiwa.dmm.com/uknow/questions/46575/)です。普段着でお越しください」でしたら、
You don't have to wear formal attire for the occasion, but just come in casual clothes.
（formal attire ＝正装）
Ordinary clothes – this is what you wear for casual every day activities.
Ordinary is simple, nothing special, the usual.
“I will just bring ordinary clothes to the weekend away”.
You can use ordinary with other types of outfits,
e.g. Ordinary work clothes
– “We are required to wear ordinary work clothes”
– meaning just the usual type of office wear. Ordinary underwear, ordinary swimsuit,
etc. Anything that isn’t special or unique.
Ordinary clothes – 普通の服 - これは日常の活動できるカジュアルな服です。
Ordinary はシンプルで、特別なものはなく、いつもという意味です。
例：“I will just bring ordinary clothes to the weekend away”.
（週末のお出かけには普段着を持っていくつもりです。）
ordinary は他のタイプの服装にも使うことができます。
Ordinary work clothes
–通常の作業服 -
例：“We are required to wear ordinary work clothes”‐
普段の作業服を着用する必要がある。
という意味です。 普通の下着、普通の水着など、特別でもユニークでもないもの。
All of these phrases are helpful as they are structured in a similar way using different synonyms.
"everyday", "casual" and "regular" are used as adjectives to describe when you would wear those types of clothes.
"clothes", "attire" and "outfit" are different words for the clothes that you wear.
There are so many ways to describe a person's style of clothing. If you want to describe the clothes you normally wear then use the words regular, standard, normal.
IE- I normally love wearing jeans. My standard attire is always casual . My regular clothing is starting to wear and tear so I need to go shopping! If you want to describe the style and the regularity of the clothes than you would use the word usual. IE " I will dress the usual way I dress" or " I will be in my usual attire tonight"
誰かの服のスタイルを表現するのにたくさんの表現方法があります。
もし、普段着るような服を説明したい場合、
“regular”, “standard”, “normal”を使うと良いでしょう。
例文
“I normally love wearing jeans.”
(私は普段ジーンズを履くのが好きです。)
“My standard attire is always casual.”
(私の普段着はいつもカジュアルです。)
“My regular clothing is starting to wear and tear so I need to go shopping!”
(私の普通の服は痛み始めています。だからお買い物に行かないとだめです。)
いつも着ているスタイルを表現したければ、
“usual”(大抵)ということができます。
例文
“I will dress the usual way I dress.”
(私はいつも着ている服を着ます。)
“I will be in my usual attire tonight.”
(私は今夜いつもの服を着ます。)
Casual wear is a style of dressing up in clothing that is relaxed, and emphasizes comfort and personal expression. Its usually not meant to impress an audience but to make the wearer comfortable and informal. You can also call it casual clothing. The noun 'clothing' is a collective noun for all types of clothes including shoes, hats, ties etc. So, you may tell someone who is struggling to find something to wear on a normal day, the following:
Its a normal day, dress up in your casual wear.
or
Since its a normal day today, wear something from your 'casual clothing' collection.
“casual wear”とは、リラックスできて、快適で、かつ自己表現している服のことです。
大抵は相手によく見せるためではなく、
着ている人を快適でカジュアルにするものです。
“casual clothing”ともいうことができます。
“clothing”という名詞は、
靴、帽子、ネクタイなどを含むすべての種類の集合名詞です。
なので、誰か普通の日に着る服を見つけるのに苦しんでいたら、
こういう風にいうことができます。
“It’s a normal day, dress up in your casual wear.”
(今日は普通の日でしょ、カジュアルに着替えなさい。)
“Since it’s a normal day today, wear something from your “casual clothing collection.””
（今日は普通の日なんだから、カジュアルな服コレクションから何か着なさい。）
*Regular Clothes. These are clothes that you wear when you are not going to any special occasion.
Example Sentences:
I'm not going anywhere today, I'll wear my regular clothes.
I didn't think she would wear her regular clothes to prom night.
“regular clothes”（普段の服）
これは、特別なイベントに行かないときに着る服です。
例文
“I’m not going anywhere today. I’ll wear my regular clothes.”
(私は今日どこにもいきません。私は普段着を着ます。)
“I didn’t think she would wear her regular clothes to prom night.”
(プロムの日に彼女が普段着を着てくるとは思いませんでした。)
Clothes that you wear on a normal day would generally be known as 'everyday clothes'. Of course, the type of clothes you wear every day may vary tremendously. You may need to be more specific. For example, there are 'everyday work clothes'. And there are 'everyday casual clothes'. If you are a policeman, then your everyday work clothes would be the uniform of a policeman. However, on going home, the policeman's everyday clothes at home, may be described as 'everyday casual clothes.'
"I wore smart casual clothing - my everyday casual clothes, to the meeting."
「普段着」は一般的に 'everyday clothes' と呼ばれます。もちろん、普段着る服は人それぞれさまざまですね。ですから、より具体的に伝える必要もあるかもしれません。例えば、'everyday work clothes'（普段の仕事着）。あるいは、'everyday casual clothes'（普段のカジュアルな服）。
警察官にとっての 'everyday work clothes'（普段の仕事着）は、制服ですね。ただ、警察官が家で着る服は 'everyday casual clothes'（普段のカジュアルな服）と表せます。
"I wore smart casual clothing - my everyday casual clothes, to the meeting."
（打ち合わせにはスマートカジュアルな服装、普段のカジュアルな服を着ていきました）
These are all words or phrases used to describe the clothes that you would wear on any regular day.
If we were to 'dress up' or where something that we wouldn't usually wear, we would call this formal attire or formal wear.
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