---
title: "The prefix un-"
description: "Spell words using the prefix un- to change meaning; understand that un- creates opposites or reverses actions"
canonical: https://lightmysky.com/learn/english/the-prefix-un-mt_zBUcAPDRPM
source: https://lightmysky.com/learn/english/the-prefix-un-mt_zBUcAPDRPM.md
retrieved: 2026-11-12
---

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# The prefix un-

Spell words using the prefix un- to change meaning; understand that un- creates opposites or reverses actions

Subject: English · Area: Spelling & Word Study · Ages 5 to 6
Page: https://lightmysky.com/learn/english/the-prefix-un-mt_zBUcAPDRPM

## Ready when they can

- Spell words with un- prefix correctly (e.g. 'unhappy', 'unfair', 'undo')
- Explain how un- changes the meaning of a word
- Create new words by adding un- to known words

## Lesson: The prefix un-

Un- is a word part called a prefix. It goes at the front of some words. It can mean not: happy becomes unhappy, meaning not happy. Well becomes unwell, meaning not well. We use un- in known words. We cannot add it to every word.

*(drawing: Put un- before happy. Keep every letter in happy.)*

**Example.** Ben says the game is unfair. He means it is not fair. Fair is the base word, the word we build on. Add un- before fair to make unfair.

To spell these words, keep the base word whole. Add u, then n, at the front. Lock becomes unlock. Tie becomes untie. Check the prefix and the base word separately. You can count the letters in each part to check that none are missing.

Un- can also reverse an action. Undo reverses something you did. Unzip opens a closed zip. Unhook takes something off a hook. Unwrap takes wrapping off. Unlock releases a lock; the door or box may still need to be opened.

*(drawing: Unzip reverses closing a zip.)*

Starting letters do not always make this prefix. Under is not un- joined to a base word der. Uncle is not un- joined to cle. Unicorn does not mean not corn or reverse corn. Check the word parts and the meaning together. Umbrella starts with um, not un.

**Recap.** Un- goes before a base word and can mean not or reverse an action. Keep the base word's spelling. Check that the word really uses this prefix.

*The lesson, practice questions and flashcards were written for this dataset.*

## Practice

24 questions on this page, each with its working shown.

## Needs first

- [Segmenting words into sounds](https://lightmysky.com/learn/english/segmenting-words-into-sounds-mt_BhYJZUsErp)
- [Phonics Vocabulary](https://lightmysky.com/learn/english/phonics-vocabulary-mt_EqXlZfB4jp)

## Opens up

- [Prefixes (age 7+)](https://lightmysky.com/learn/english/prefixes-age-7-mt_T6nrrf2K43)