為爛路造的東西
第一族形容「東西」：它被造出來就是要跨出那條路面，所以底盤要高、輪胎紋路要深。
adjective · B1
Built strong enough to be driven on rough ground — mud, sand, stones or steep hills — as well as on ordinary roads.
越野的
核心畫面
off- means away from, and road means the smooth made way that everybody normally uses. Put the two together and you get one picture: leaving that smooth surface behind and going onto whatever ground happens to be there — mud, sand, gravel, grass. Everything the word does comes from that step off the edge of the road.
off- 可以想成「離開」，road 是大家平常在走的那條鋪好的路。兩個字合起來，畫面就是：離開那條平整的路面，踩到…更多收起
off- 可以想成「離開」，road 是大家平常在走的那條鋪好的路。兩個字合起來，畫面就是：離開那條平整的路面，踩到旁邊原本的地上——泥巴、沙、碎石、草地。這個字後面的每一種用法，都像是從「跨出路面那一步」長出來的。From the word’s history
Wiktionary gives the formation plainly: off- + road, with road going back through Middle English rode to Old English rād.
Wiktionary 直接寫明它的構成：off- 加 road。road 這個字則可以往回追到中古英文 rode、古英文 rād。
Wiktionary, entries “off-road” (adj and verb): “From off- + road.”
Three branches
在爛路上進行的事
第二族形容「事情和路線」：真正跨出路面的動作發生了，所以講的是活動本身。
adjective · B1
Taking place on rough ground away from paved roads, or leading over such ground.
野地的；越野路線的
不在馬路上的位置
第三族把 road 讀成「公共道路」而不是「鋪好的路面」，所以 off 的是馬路這個空間，不是柏油。
adjective · B2
Used about parking: not on the public road, but on private ground beside a building, such as a driveway or a small yard.
不佔用馬路的（停車）