An augmentative (abbreviated aug) is a morphological form of a word which expresses greater intensity, often in size but also in other attributes. It is the opposite of a diminutive.

Overaugmenting something often makes it grotesque and so in some languages, augmentatives are used primarily for comical effect or as pejoratives.

Many languages have augmentatives for nouns, and some have augmentatives for verbs.

In modern English, augmentatives can be created with the prefixes:

Since the early 1990s, the prefix "über-" or "uber-" has also frequently been used as a borrowing from German. The suffix -zilla (from Godzilla), expressing a monstrous quality, can also be considered an augmentative form.

In some parts of the United Kingdom and the Republic of Ireland, the prefix "old" is used as an augmentative, and a pejorative in some cases. An example of this is using "old’un" or "old one" to describe one's parents/grandparents.

In modern Dutch, as in English, augmentatives are usually created with the prefixes:

There are also prefixes that can be used for some adjectives: