Not telling the truth. It works on two things. About a person, it means they are lying, or are the kind of person who lies: 'an untruthful child', 'he was untruthful about where he had been'. About a statement, report, or advertisement, it means the content is false: 'an untruthful account of the meeting', 'untruthful advertising'.

Not telling the truth不說實話。It works on two things它可以用在兩種東西上。About a person用在人身上時, it means they are lying, or are the kind of person who lies意思是他在說謊，或是那種會說謊的人: 'an untruthful child'『an untruthful child』（愛說謊的小孩）, 'he was untruthful about where he had been'『he was untruthful about where he had been』（他對自己去過哪裡說了謊）。About a statement, report, or advertisement用在陳述、報告或廣告上時, it means the content is false意思是內容不實: 'an untruthful account of the meeting'『an untruthful account of the meeting』（不實的會議紀錄）, 'untruthful advertising'『untruthful advertising』（不實廣告）。

Like 'untruth', it is the measured, formal choice — a school report, a legal finding, or an official complaint will say 'untruthful' where a friend would just say 'lying'.

Like 'untruth'跟『untruth』一樣, it is the measured, formal choice這是比較拿捏過、正式的用字 — a school report, a legal finding, or an official complaint will say 'untruthful'學校的報告、法律的裁定，或正式的申訴會用『untruthful』 where a friend would just say 'lying'而朋友之間就只會說『lying』。

There is a small difference worth feeling: 'untruthful' points at a habit or a character more than at one moment. Calling one sentence untruthful is fine, but calling a person untruthful suggests this is how they generally are, not a single slip. Watch the pattern too — you say untruthful ABOUT something ('untruthful about his age'), not 'untruthful of'.

There is a small difference worth feeling有個細微但值得感受的差別: 'untruthful' points at a habit or a character more than at one moment『untruthful』指的比較是習慣或人格，而不是某一個當下。Calling one sentence untruthful is fine說某一句話untruthful沒問題, but calling a person untruthful suggests this is how they generally are但說一個人untruthful，暗示的是他一貫的樣子, not a single slip而不是偶爾一次失誤。Watch the pattern too也要注意搭配的介系詞 — you say untruthful ABOUT something你會說untruthful ABOUT某件事 ('untruthful about his age')（『untruthful about his age』）, not 'untruthful of'而不是『untruthful of』。