This is an idiom meaning the person is quick thinking and fast to react to situations. You can use this for people who are quick with jokes, they are fast with comebacks. It can also be used to describe people who are always alert in work or in sport.
"You're always on the ball".
"You're on the ball this morning".
これは頭の回転が速く、状況に素早く対応する人という意味のイディオムです。冗談に対する反応が早く、返しが早い人にこれを使うことができます。また、常に仕事やスポーツで冴えている人を表すのにも使用できます。
【例文】
"You're always on the ball".（いつも頭の回転が速いね）
"You're on the ball this morning".（今朝は冴えてるね）
She has great charisma, is mentally sharp and makes witty retorts
It seems that this person would make a great guest at any meal or party. Apart from her intellect it seems she also has a good sense of humour and it is often said of this type of person that they have 'great charisma,' which means they make a favourable impression on most people that they meet.
Erudite means having or showing great knowledge or learning:
"Ken could turn any conversation into an erudite discussion."
A retort = a comeback
この方は、食事やパーティーで素晴らしいゲストになりそうですね。知性とは別にユーモアのセンスもあり、こういったタイプの人は「偉大なカリスマ」があると言われ、会う人の多くに好印象を与えます。
Eruditeとは、大きな知識や学識があるまたはそれを示すという意味です。
【例文】
"Ken could turn any conversation into an erudite discussion."（ケンはどんな会話でも博学な議論に変えることができる）
A retort = 返し
The most simple way of saying this is "I love how clever and witty she is". Witty simple means in conversations she is quick at making good jokes. A common phrase that we use in England for being quick and alert is "on the ball". Or you could describe someone as 'sharp' which refers to them being clever and mentally quick!
最もシンプルな言い方は "I love how clever and witty she is"（頭の回転が速く手返しがうまいところが好き）です。
"witty" は、会話で素早くうまいジョークを言う人をいいます。
"on the ball" は機敏で抜け目ない人を表すイングランドでは一般的なフレーズです。
または、'sharp' と表すこともできます。これは、賢くて頭の回転が速い人をいいます。
"I love how she's really clever and always makes witty comebacks"
"She is really on the ball with her intelligence and her witty comebacks"
"She has brilliant banter"
If you are asked what you like about a certain person, who happens to be female and you would like to explain that you like how she is very clever and can make witty remarks, you could say any of the following: "I love how she's really clever and always makes witty comebacks", "She is really on the ball with her intelligence and her witty comebacks" or "She has brilliant banter".
ある人（女性）のどこが好きか尋ねられて、頭の回転が早くて返しが上手いところだと答えたいなら、次のように言えます。
"I love how she's really clever and always makes witty comebacks"（頭の回転が早くて返しが上手いところが好き）
"She is really on the ball with her intelligence and her witty comebacks"（彼女は頭の回転が早くて返しが上手い）
"She has brilliant banter"（彼女は冗談が上手い）
All of these expressions are common English expressions. Clever clogs and Ms smarty pants are meant to be playful banter directed at someone that knows something you didn't know or were slow at answering yourself.
As far as rapier wit goes, it carries the idea of cutting, sharp and cleanly. To have rapier wit, your comments would be sharp and somewhat sarcastic but at the same time playful. Always remember - Sarcasm is the lowest form of wit...BUT...wit is the highest form of humor!
He can think fast and respond in funny ways to what people say.
おっしゃられている内容は以下のようにも表現できると思いました(*^_^*)
He can think fast and respond in funny ways to what people say.
「直訳： 彼は素早く考えることができ、面白いふうに人々の言うことに反応できる」
think fastは「頭の回転が速い」というニュアンスで使えます。
respond to ～「～に応答する」
in funny ways「おもしろいふうに」
以上です。
少しでも参考になれば幸いです(*^_^*)
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