Tactlessly is the adverb: it describes HOW someone did or said something — in a way that upset or embarrassed people, without meaning to. Because it is an adverb, it attaches to a verb, and the most common verbs it goes with are verbs of speaking: to say something tactlessly, to ask tactlessly, to remark tactlessly, to blurt something out tactlessly. You also see it at the front of a clause, commenting on the whole thing: 'Tactlessly, he mentioned her age in front of everyone.' As with the adjective, the word says the person was clumsy rather than cruel — they did not read the room.

Tactlessly is the adverb Tactlessly是副詞 it describes HOW someone did or said something它形容一個人做了或說了什麼「的方式」 in a way that upset or embarrassed people用一種讓人不高興或尷尬的方式 without meaning to而且不是故意的 Because it is an adverb因為它是副詞 it attaches to a verb它會接在動詞上 and the most common verbs it goes with are verbs of speaking而最常搭配它的是跟說話有關的動詞 to say something tactlessly白目地說出某件事 to ask tactlessly白目地問 to remark tactlessly白目地評論 to blurt something out tactlessly白目地脫口而出 You also see it at the front of a clause你也會看到它放在子句最前面 commenting on the whole thing用來評論整件事 'Tactlessly, he mentioned her age in front of everyone.'「白目地，他當著大家的面提到她的年紀」 As with the adjective就跟那個形容詞一樣 the word says the person was clumsy rather than cruel這個字說的是這個人笨拙而不是刻薄 they did not read the room他們沒有讀懂場面

One thing worth knowing: in real English this adverb is less common than the adjective. Native speakers more often say 'it was tactless of him to mention it' than 'he tactlessly mentioned it'. The adverb sounds slightly more written, more like a novel or a newspaper.

One thing worth knowing有一件事值得知道 in real English在真實的英文裡 this adverb is less common than the adjective這個副詞比形容詞少見 Native speakers more often say母語者更常說 'it was tactless of him to mention it'「他提那件事真是白目」 than 'he tactlessly mentioned it'而不是「他白目地提到那件事」 The adverb sounds slightly more written這個副詞聽起來比較書面 more like a novel or a newspaper比較像小說或報紙的用語

Both are correct, so you can use it, but if you want the everyday version, the 'it was tactless of someone to do something' pattern is the safer choice.

Both are correct兩種說法都對 so you can use it所以你可以用這個副詞 but if you want the everyday version不過如果你想要日常一點的版本 the 'it was tactless of someone to do something' pattern「it was tactless of someone to do something」這個句型 is the safer choice是比較保險的選擇