Tactless describes a person, or a thing they say or do, that hurts or embarrasses someone because they did not think about how it would land. The key is that there is no cruelty behind it. A tactless person is not trying to wound you; they simply said the true thing at the wrong moment, or in front of the wrong people. Asking a woman when the baby is due when she is not pregnant is tactless. Telling your friend at their birthday dinner that their new haircut makes them look older is tactless. Compare it with 'rude', which is the word most students reach for: rude often means the person knew and did not care, while tactless means they did not notice. That is why tactless is a softer criticism — it says clumsy, not nasty. It is used about people ('he's completely tactless'), and about the things they produce: a tactless remark, a tactless question, a tactless email. The feeling of the word is neutral-to-mildly-formal; it fits in normal conversation and in writing, and it is a common polite way to complain about someone without calling them a bad person. The positive opposite is 'tactful', and the noun behind both is 'tact', which is the ability to feel what other people can bear to hear.

不得體、白目、不會看場合說話。台灣口語最接近的是「白目」，但 tactless 沒有「故意找碴」的意思，比較是「沒想到會傷到人」；書面可用「說話不圓融／不懂得拿捏分寸」。