今日は直行直帰ですって英語でなんて言うの？

簡単な英語で言えますので、ぜひ１つ１つ表現してみてください。

例えば、
家から直接行きます。
I will go directly from my house.
そして、今日は会社には戻りません。
I'm not going back to the office today.

そんな感じで通じますよ。

'straight to' や 'right back' を使うと「まっすぐ行ってまっすぐ帰る(寄り道せずに)」と言う印象が伝わりやすいです。

同僚にさらっと伝えるときは、これぐらいカジュアルな表現で良いでしょう。

「今日は直行直帰です〜」
"I'm going straight to the client site and back today, and I'm not stopping by the office".

"straight to"は「直接」「真っ先に」と言ったニュアンスを伝えたいときに使えます。
"client site"は「客先」、
"stop by"は「立ち寄る」ということを表現にするときに使われる表現です。

I'm going straight home today =今日は真っ直ぐ帰るよ

I'm going straight home after work =仕事が終わったら真っ直ぐ帰るよ

after workとわざわざ言わなくても意味は伝わるはずです。どうしても寄り道できない事を強調する場合は:

I have to go straight home today =今日は真っ直ぐ帰らなきゃいけないんだ

と”have to”と言うフレーズを使いましょう。

There are a couple of ways to express a direct journey.
"I'll be going straight home after visiting the client." is probably the most simple, simply stating what you ARE going to do, leaving out what you won't be doing.
If you do want to be more specific and include what you WON'T be doing you can expand into a phrase like: "I won't be stopping back at the office after my meeting with my client, I will be going straight home.".
And finally, if you simply want to say what you won't be doing, you can simply say "I won't be back at the office today.".
All options provide the statement of a direct journey; you can just choose what you would like to say you are or aren't doing.

It's interesting how I was trying to think of one word or common phrase for this in English, but I couldn't think of any! Instead I have given a few examples of sentences I would use in this situation: "I'll be going home straight from my meeting.." or "I won't be stopping by the office after my meeting." are ways to briefly explain what your plan is.

I hope this helps. :)

You wish to explain to a coworker that you are going directly to the client's place, and then directly home later. Either of the above two examples will be adequate for that scenario.
directly = straight

1. You won't see me in the office today as I have an offsite appointment.
   This means that you will be going straight to the client's office and will be
   in meetings at that office all day. It goes without saying that you will be
   going straight home after visiting the client so will not be coming into the
   office. The word ''offsite'' is the opposite of onsite and means not at
   your office.

2. I'll be going straight to the client so will not be coming in to the office
   today.
   "Straight" means that you will not be making a turn at the office before
   your appointment with the client. ''Not coming in today'' obviously means
   that you will go home after the appointment.

There are occasions when it makes no sense to appear in the office when our tasks take us far away. This means we will probably need to communicate this reality to our associates so that they will be aware of our work schedule and not worry about our non-appearance.

After I go to the client's place I am going straight home.
I am going straight home after the client's place.
I won't be coming back to the office after I go to the client's place.

When you want to tell a coworker that you are going home straight after going to a client's place and not coming back to the office, then you can say one of these three sentences.

I hope this helps.
Have a great day.
Will

In this situation: today I am going to my client's place, after that I am going straight home. You don't need to explain that you will go to the office, because you have already explained the fact that you are going straight home after going to the clients place.

Notice in the first two examples that we are allowed to have sentence movement between our two clauses while also maintaining the same meaning. We can also use the present progressive or the future tense when talking about going home.

You could use any of the above sentences to state your whereabouts and that you will not be stopping at your own office along the way.

• Straight; exactly from a place to another.
• Directly; exactly from a place to another place and no stops in between.