Compound names indicate modifiers that can boost the strength, speed, or effects of a weapon on the wielder. Not all modifiers are implemented yet. I don't think a reinforced weapon is any different from a regular one but a weapon of seduction or a spidersilk one will boost some of your stats or skills. They also may require minimum stats to be equipped. Oh! And I think you missed a name. "Encrusted" usually goes with a gem (diamond, ruby, amethyst, etc.).
So, if you loot a weapon like that you probably want to keep it, if not for the potential boost it may give you, for its funny name.
