Not having the qualities you would normally expect from that kind of person, thing, or group — different from the usual example. 'A typical Taiwanese breakfast' is what you expect; 'an untypical Taiwanese breakfast' is one that surprises you. It usually appears with 'of': untypical of him, untypical of the region, untypical of this company. Here is the thing your dictionary may not tell you: English has two words for this, 'untypical' and 'atypical', and 'atypical' is far more common. 'Atypical' is the standard choice in science, medicine, and statistics ('atypical cells', 'an atypical case'). 'Untypical' is the plainer, more everyday one, more common in British writing, and it tends to describe behaviour or a moment rather than a technical category — 'It was untypical of her to shout.' Neither is wrong; they simply sit in different rooms. And note the tone: untypical is neutral. It says 'different from usual', not 'wrong' and not 'special'.

不典型的、與平常不同的（常說「不像他平常的樣子」）