struct

The least obvious member. in- (into) + struere (build) = "to build into." To instruct someone is to stack knowledge *into* their mind, layer by layer, like a builder laying courses of brick. That's why teaching, training, and giving orders all share this word — each "builds something into" the listener.

From Latin instrumentum, "equipment for building/doing." An instrument is literally a tool you build with — which is why one word covers a hammer, a violin, a thermometer, and a legal document: each is a crafted tool for accomplishing something. The musical sense came later, from "a tool for making sound."

de- (down, reversal) + struere (build) = to un-build, to take the stack apart. Note the spelling split: the verb destroy was worn down through Old French destruire, while the noun destruction kept the original Latin look. Same root, two faces — a classic verb/noun spelling pair.

The purest form: just struct + -ure (act/result). A structure is "the thing that's been built" — the arrangement of stacked parts. That's why it stretches from concrete (a building, a bridge) to abstract (sentence structure, organizational structure): anything whose parts are arranged into a whole has a structure.

ob- (against, in the path of) + struere (build) = to build a barrier across someone's way. The image is a pile of rubble blocking a road. This explains "obstruction of justice" — you're not destroying justice, you're piling obstacles in its path so it can't move forward.