Word Classes & Vocabulary
Understand the different types of words, and learn how prefixes and suffixes change meaning.
The Five Main Word Classes
Every word in a sentence has a job. We group words by the job they do. These groups are called word classes (also known as parts of speech).
A word that names a person, place, thing, or idea.
Examples: teacher, London, happiness, dog, courage
A word that shows an action or a state of being.
Examples: run, think, is, believe, climbed
A word that describes a noun, telling you more about it.
Examples: tall, beautiful, three, ancient, shiny
A word that tells you how, when, where, or how much.
Examples: quickly, yesterday, very, often, carefully
A word that shows the relationship between a noun and other words (often about position or time).
Examples: on, under, between, during, after
Spotting Word Classes in a Sentence
See how each word has a different role.
Example Sentence
The young fox jumped quickly over the tall fence.
Prefixes and Suffixes
A prefix is added to the beginning of a word to change its meaning. A suffix is added to the end. Learning these helps you build and understand new words.
Common Prefixes
un- (not / opposite)
happy → unhappy | kind → unkind
re- (again)
do → redo | build → rebuild
dis- (not / opposite)
agree → disagree | appear → disappear
mis- (wrongly)
understand → misunderstand | lead → mislead
pre- (before)
view → preview | heat → preheat
Common Suffixes
-ful (full of)
hope → hopeful | care → careful
-less (without)
hope → hopeless | care → careless
-ment (the result of)
enjoy → enjoyment | amaze → amazement
-ness (state of being)
kind → kindness | sad → sadness
-ly (turns adjective into adverb)
quick → quickly | careful → carefully
Word Origins and Roots
Many English words come from Latin, Greek, and other languages. Knowing the root of a word can help you work out the meaning of unfamiliar words.
aqua (Latin: water)
aquarium, aquatic, aqualung
tele (Greek: far away)
telephone, television, telescope
port (Latin: to carry)
transport, export, portable
rupt (Latin: to break)
erupt, interrupt, disrupt
graph (Greek: to write)
autograph, photograph, graphic
dict (Latin: to say)
dictionary, predict, contradict
Key Vocabulary
Word Class
A category of words based on the job they do in a sentence (noun, verb, adjective, adverb, preposition).
Prefix
A group of letters added to the beginning of a word to change its meaning.
Suffix
A group of letters added to the end of a word to change its meaning or word class.
Root Word
The base form of a word before any prefix or suffix is added.
Synonym
A word with the same or similar meaning (e.g., happy / joyful).
Antonym
A word with the opposite meaning (e.g., happy / sad).
Worked Examples
See how to identify word classes and build new words with affixes.
Example 1: Identify the adjective
"The enormous elephant drank from the river."
Answer: enormous — it describes the noun "elephant", telling us about its size.
Example 2: Build words with prefixes
Root word: agree
disagree (opposite) | disagreement (added suffix too — the state of not agreeing)
Example 3: Change word class with a suffix
Root word: care (noun/verb)
careful (adjective — full of care) → carefully (adverb — in a careful manner)
Knowledge Check
Test your understanding of word classes and vocabulary. Select the correct answer and click "Check Answer".
Question 1
In the sentence "The brave knight rode quickly," what word class is "quickly"?
Question 2
What does the prefix "un-" mean?
Question 3
Which word is a preposition in this sentence? "The cat slept under the table."
Question 4
If "hope" is the root word, what does "hopeless" mean?
Question 5
The root "tele" means "far away". What does "telescope" most likely mean?
Key Concepts Summary
- ● The five main word classes are nouns, verbs, adjectives, adverbs, and prepositions.
- ● Prefixes (un-, re-, dis-, mis-, pre-) are added to the beginning of words to change meaning.
- ● Suffixes (-ful, -less, -ment, -ness, -ly) are added to the end to change meaning or word class.
- ● Knowing word roots (aqua, tele, port, rupt) helps you decode unfamiliar words.
- ● Every word in a sentence has a job — identifying it helps you understand and write better sentences.