OUs

The suffix -ous is an English derivational suffix used to form adjectives meaning “full of” or “having the quality of” from bases such as nouns or other adjectives. Words with -ous describe a characteristic or condition, for example dangerous, curious, nervous, glorious, and numerous. It does not create verbs or stand-alone nouns.

Origin and history: The form comes from Latin -osus via Old French into Middle English. The Latin suffix -osus signified “full of” and was used to convert stems into adjectives. English borrowed many -osus adjectives with their senses unchanged, often adjusting spelling to fit English phonology.

Formation and semantics: -ous adjectives can derive from nouns (danger → dangerous) or from Latin roots. They describe physical or abstract properties, such as danger, heat, or curiosity. The same suffix yields a wide range of meanings and may carry positive or negative connotations depending on context.

Spelling and relatives: English also has related suffixes -eous and -ious, from the same Latin origin. The choice among -ous, -eous, and -ious is historical and not always predictable; dictionaries are the best guide for spelling and meaning. The ending is usually pronounced as /əs/.

Notes: The suffix is productive but not universal; some bases do not form -ous adjectives, and some -ous words are highly specialized. Understanding the root often helps infer meaning, but exceptions are common in English.