harmful
/ˈhɑɹmfl̩/adjective
harmful is spelled H-A-R-M-F-U-L: 7 letters and 2 syllables. It appears 9.3 times per million words in written English, the 7,445th most frequent word form (wordfreq, 2021 data). As an adjective, harmful means “Causing or likely to cause harm or damage; injurious” (English Wiktionary, September 2026).
How many letters and syllables are in harmful?
| Letters | 7: H-A-R-M-F-U-L |
|---|---|
| Syllables | 2 (from its American pronunciation) |
| In writing | 9.3 times per million words; the 7,445th most frequent word form |
| Wrong spellings searched | none measured in search |
Sources: letters and syllables from the English Wiktionary's hyphenation or pronunciation and the CMU Pronouncing Dictionary; written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How common is harmful?
Harmful appears 9.3 times per million words in written English, the 7,445th most frequent word form in the list.
Source: written frequency: wordfreq 3.1 (a 2021 snapshot of Wikipedia, subtitles, news, books, web text and social media).
How do you pronounce harmful?
- UK /ˈhɑːmfl̩/
- US /ˈhɑɹmfl̩/
Harmful has 2 syllables (counted from its American pronunciation in the CMU Pronouncing Dictionary).
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Recordings: En-us-harmful.ogg, Wikimedia Commons (author and licence on each file's page).
Forms of harmful
- harmfuller comparative
- more harmful comparative
- harmfullest superlative
- most harmful superlative
- harmfull
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
What does harmful mean?
The meanings the English Wiktionary records, quoted as written there (source below).
adjective
- 1
Causing or likely to cause harm or damage; injurious.
Wear a hat to protect your skin from harmful sunlight.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).
Harmful in Spanish, French, German and Portuguese
In the sense likely to be damaging:
| Language | Words |
|---|---|
| French | dangereux, nuisible, nocif, préjudiciable |
| German | schädlich |
| Portuguese | prejudicial, nocivo, danoso, daninho |
| Spanish | perjudicial, perjudicador, lesivo |
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract). Translations are Wiktionary's, by sense; a linked word has its own PlainSpell page.
Where does harmful come from?
From Middle English harmful, from Old English *hearmful (suggested by hearmfullīċ (“harmful; hurtful”)), equivalent to harm + -ful.
Source: English Wiktionary, dump of September 2, 2026 (CC BY-SA 4.0), through kaikki.org (Wiktextract).