Select the most appropriate one-word substitution for the given group of words.

A supplementary document to a will 

Codicil

The most appropriate one-word substitution for "a supplementary document to a will" is codicil.

• Velleity is a weak or half-hearted desire.
• Imbecile is a now-obsolete term for a person with a mild intellectual disability.
• Post-will is not a real word.
• Codicil is a legal document that amends or adds to a will. It must be signed and witnessed in the same way as the will itself.