# IDF vs iffy

> English confusable word pair

## The two words

### IDF
*noun · frequency rank #19,861*
Initialism of inverse document frequency.

### iffy
*adjective · IPA /ˈɪfi/ · frequency rank #37,981*
Of dubious authenticity, legitimacy or legality.

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