Glossary
suffix
A suffix is a word part added to the end of a root. It can change the meaning and, unlike a prefix, it usually changes the word's part of speech.
A suffix is a word part fixed to the end of a root word. It can shift the meaning, and it very often shifts the word's part of speech as well: care becomes careful (an adjective), carefully (an adverb) and carelessness (a noun). That last property is what makes suffixes worth knowing — a suffix tells you what role a word is playing in a sentence even when the word itself is new to you.
The common families: -ous and -ful (full of), -less (without), -able and -ible (can be), -ity and -ness (the state of), -ment (the result of), -ize and -ify (to make), -ate (to do or make), -tion and -sion (the act or result of), -ly (in the manner of).
Reading a suffix is also a check on a choice. A question asks what a word means, and one option is the right idea wearing the wrong ending — a noun where the sentence needs an adjective. The suffix is how you catch that without knowing the definition. Watch the split point: the -er in summer is not a suffix.
Taught in
Related terms
- prefix — A prefix is a word part added to the front of a root that changes its meaning — un-, re-, pre-, sub- and trans- among them. Learning a few unlocks dozens of words.
- word root — A word root is the part of a word carrying its core meaning, with prefixes and suffixes built onto it. Most English roots come from Latin or Greek, and one root usually builds a whole family.
Source: Official ASVAB — subtest descriptions (what each subtest asks) and the CAT-ASVAB scored-question counts (accessed 2026-09)