English prefix

English prefixes are affixes (i.e., bound morphemes that provide lexical meaning) that are added before either simple roots or complex bases (or operands) consisting of (a) a root and other affixes, (b) multiple roots, or (c) multiple roots and other affixes. Examples of these follow:

• undo (consisting of prefix un- and root do)
• untouchable (consisting of prefix un-, root touch, and suffix -able)
• non-childproof (consisting of prefix non-, root child, and suffix -proof)
• non-childproofable (consisting of prefix non-, root child, root proof, and suffix -able)

English words may consist of multiple prefixes: anti-pseudo-classicism (containing both an anti- prefix and a pseudo- prefix).

In English, all prefixes are derivational. This contrasts with English suffixes, which may be either derivational or inflectional.