Superfluous
Etymology
From Latin "superfluus," "overflowing," from "super" ("over, above") and "fluere" ("to flow"). The image is of a vessel already full and spilling over. English kept that sense of running past the point of need — present beyond what the situation requires.
adjective · /soo-PUR-floo-us/
More than is needed; unnecessary because enough is already present.
What it names
Reach for it when something is excess to requirements rather than actively harmful — the superfluous word, the superfluous step, the part you could cut without loss.
Example
Once she had the exact figure, all his rough estimates were superfluous.
Related idea
Compare extraneous: the extraneous item doesn’t belong to the matter at all, while the superfluous item does belong but is simply surplus.