Look around any English text and you will find adjectives ending in -OUS everywhere: famous, jealous, dangerous, nervous, generous, ridiculous. Hundreds of words share this ending, and they all share one sound. The rule is one of the most reliable in the language.
The Rule in One Line
The adjective suffix -OUS is unstressed and pronounced /əs/ — schwa plus a soft S. The OU letters do not say their usual sound; they collapse to a neutral schwa.
Practice the Pattern
The Stress Rule That Comes With It
-OUS is unstressed, so it always pulls your attention to the syllable just before it. The result is a tidy stress pattern: stress on the syllable before -OUS, soft schwa on the suffix.
- FA-mous, JEA-lous, NER-vous
- DAN-ger-ous, GE-ner-ous
- eNOR-mous, riDI-cu-lous
For longer words like generous and dangerous, the syllable right before -OUS may also reduce, but the suffix itself never gets the stress.
Why It Sounds So Calm
The OU in this suffix is a fossil from Old French. It was originally a full vowel, but English has reduced unstressed vowels for centuries. Today the spelling is preserved while the sound has collapsed to the all-purpose /ə/.
Special Cases You Already Know
When other letters sit before -OUS they create well-known sub-patterns:
- -cious /ʃəs/ — delicious, precious, suspicious. The CI palatalises into SH, and the OUS is still /əs/.
- -tious /ʃəs/ — ambitious, cautious, infectious. Same story with a T.
- -geous /dʒəs/ — courageous, gorgeous, outrageous. The G softens to /dʒ/.
- -uous /uəs/ ~ /juəs/ — continuous, strenuous, ambiguous. Two-syllable suffix.
Even in those clusters, the OUS at the very end is still /əs/.
Common Mistakes
- Saying fam-OWS with a long /aʊ/. Wrong; the OU is a schwa.
- Stressing the suffix: jea-LOUS. The right pattern is JEA-lous.
- Pronouncing the final S as /z/. The S in -OUS is voiceless /s/, never /z/.
Quick Reference Table
| Word | IPA | Stress |
|---|---|---|
| famous | /ˈfeɪməs/ | FA-mous |
| jealous | /ˈdʒɛləs/ | JEA-lous |
| dangerous | /ˈdeɪndʒərəs/ | DAN-ger-ous |
| nervous | /ˈnɜːrvəs/ | NER-vous |
| generous | /ˈdʒɛnərəs/ | GE-ner-ous |
| ridiculous | /rɪˈdɪkjələs/ | ri-DI-cu-lous |
| enormous | /ɪˈnɔːrməs/ | e-NOR-mous |
Self-Test
Read aloud, all ending in soft /əs/:
- famous
- jealous
- nervous
- generous
- dangerous
- ridiculous
- enormous
- obvious
- marvelous
- numerous
Summary
Whenever you see -OUS at the end of an English adjective, say /əs/. Stress sits on the syllable just before the suffix. One short rule covers a vast and very useful family of adjectives.