expression
with shoes on; without removing shoes
Literal meaning: entering or stepping somewhere while still wearing outdoor shoes. Often used in prohibitions or descriptions of indoor spaces.
土足で上がらないでください。
Please do not enter with your shoes on.
この部屋は土足で入っても大丈夫です。
It's okay to enter this room with shoes on.
expression
rudely; thoughtlessly; trampling on
Idiomatic use, often in the forms 土足で踏み込む or 土足で踏みにじる, meaning to intrude on someone's feelings, privacy, or rights in a crude, insensitive way.
彼のプライバシーに土足で踏み込むようなことはやめてほしい。
I wish you wouldn't trample on his privacy like that.
人の気持ちを土足で踏みにじる発
It was a remark that trampled on people's feelings.