# deleterious

> English word · Adjective · IPA /ˌdɛl.ɪˈtɪə̯.ɹi.əs/ · frequency rank #40,647

## Definitions
1. Harmful, often in a subtle or unexpected way.
2. Having lower fitness.

## Etymology
Adapted borrowing (1640s; 1582 as deletorious) of New Latin dēlētērius, dēlētōrius + -ous, from Ancient Greek δηλητήριος (dēlētḗrios, “noxious, deleterious”), from δηλητήρ (dēlētḗr, “a destroyer”), from δηλέομαι (dēléomai, “I hurt, damage, spoil, waste”). Not related to delete or deleble. Doublet of deletery.

## Common misspellings (15)
`ddeleterious`, `deelterious`, `deleetrious`, `deleteirous`, `deleteriosu`, `deleteriouss`, `deleteriuos`, `deleteroius`, `deleterrious`, `deletreious`, `deletterious`, `delleterious`, `delteerious`, `dleeterious`, `edleterious`

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/deleterious