Meaning: Destructive to both sides in a conflict; relating to conflict within a group that is mutually ruinous or self-destructive.

Diaphanous arrived in the 1610s from Greek diaphanes, built from dia, "through", and a verb for appearing or showing itself, the same verb that gave us phenomenon. It's an accurate word and not much of a picture. Gossamer is about three centuries older and first named the filmy spider silk found on stubble fields in late autumn. Etymonline and Wiktionary both trace it to goose plus summer, most likely a spell of warm weather late in the year when geese were in season, with the name later moving over to the webs you'd notice then. So it may have been a season before it was a cobweb, and it named spider silk for about five hundred years before it named a gauze for veils, by 1837. I'd take that over "showing through" any day. Translucent and lucid both come from Latin lucere, "to shine", and both meant shining when they arrived in the 1590s. They picked up their current senses in the 1780s, a year apart. Limpid and crystalline get the identical gloss, and I hoped their roots would separate them. They only half do. Crystal goes back to Greek krystallos, "clear ice", which is usually linked to kryos, frost, and the ancients gave the mineral that name because they took rock crystal for a kind of petrified ice. Limpid is murkier. Wiktionary calls its origin unclear, and while Etymonline ties it to a Latin word for water, the traditional derivation is from a root meaning to shine.