Superfluous means more than is needed, and therefore useless. Take it away and nothing is lost.
It describes words, parts and people, and the most common use is about writing, since cutting superfluous words is most of what editing is. It is formal and slightly grand, which is a small irony for a word meaning unnecessary. It takes to when a purpose is named. The literal Latin sense is overflowing, which is exactly the picture: more than the container needs. Redundant is the everyday equivalent.
1adjectivesuperfluousMore than is needed and therefore unnecessary.
“The last paragraph is entirely superfluous.”
Superfluous is overflowing. Latin super, over, plus fluō, to flow, so what is superfluous has spilled over the top, which is precisely what the Germanic word overflow says.
Latin
superfluus — superfluous
Middle English
superfluous
English, today
superfluous
Built from
From Middle English superfluous, from Latin superfluus (“superfluous”) + -ous, from superfluō (“overflow”), from super (“above, more than, over”) + fluō (“flow”). Compare mellifluous and fluid, also from Latin. Literally corresponds to overflow, which is from Germanic, rather than Latin.
Etymology from Wiktionary, CC BY-SA