If someone is buttoned-up, they keep their feelings inside. They do not show warmth easily, and they are especially awkward or silent about sexual feelings. The picture comes from clothes: a shirt buttoned all the way to the neck, nothing loose, nothing showing — so the person feels tightly closed.

If someone is buttoned-up如果一個人 buttoned-up，they keep their feelings inside他們會把感情藏在心裡。They do not show warmth easily他們不容易表現出溫暖，and they are especially awkward or silent about sexual feelings尤其是對於性方面的感覺特別彆扭或沉默。The picture comes from clothes這個畫面是從衣服來的：a shirt buttoned all the way to the neck一件扣到脖子的襯衫，nothing loose, nothing showing沒有一點鬆開，什麼都沒露出來——so the person feels tightly closed所以這個人給人的感覺就是緊緊封閉的。

It is informal, a little like newspaper or novel English, and often a bit critical or pitying, as if they cannot relax. This sense is about character, not about whether their jacket is actually buttoned.

It is informal這個字用法上不太正式，a little like newspaper or novel English有點像報紙或小說裡的英文，and often a bit critical or pitying而且常常帶點批評或憐憫的意味，as if they cannot relax好像在說這個人沒辦法放鬆。This sense is about character這個意思講的是性格，not about whether their jacket is actually buttoned而不是他的外套是不是真的扣起來。

English also uses buttoned up for a job that is fully arranged, or a coat done up, but here it means emotionally closed. It is close to reserved or inhibited — not sweet shyness, and not the quiet person who is secretly full of fire.

English also uses buttoned up英文也會用 buttoned up for a job that is fully arranged來指一件完全安排妥當的事，or a coat done up或一件扣好的外套，but here it means emotionally closed但在這裡它的意思是情感上封閉。It is close to reserved or inhibited它跟 reserved 或 inhibited 很接近——not sweet shyness不是那種可愛的害羞，and not the quiet person who is secretly full of fire也不是那種表面安靜、心裡其實很有火的人。