Words can be simple or complex. A simple word consists solely of a base or root word, which can not be broken down into smaller units. A base carries the essential meaning of a word.

A word can also consist of a base with one or more affixes. There are three types of affix in Indonesian: prefixes, suffixes and circumfixes or confixes:

1. a prefix is attached before the base,
2. a suffix comes after the base and
3. a circumfix or confix contains two parts, one occurring before the base and one after.

However, not all base words can be combined with affixes, nor are they always consistent in their subsequent usage and meaning.

Indonesian suffixes are -kan, -i, -an and -nya. They can form a noun; can soft a command or add politeness; can direct the action; and derives causatives or adjectives.