na-adjective, noun
rude; presumptuous; cheeky; outspoken
Describes behavior or speech that lacks restraint or consideration for others, often crossing social boundaries. Can range from mild cheekiness to outright rudeness.
彼の無遠慮な発言に、みんな驚いた。
Everyone was surprised by his rude remark.
無遠慮に人の家
Please don't barge into someone's house without consideration.
Compound of 無 (without) and 遠慮 (restraint, reserve). The word 遠慮 itself comes from Chinese, and the combination follows a common pattern of negation with 無.