What this suffix does
-defined evaluates how clear the boundaries or meaning of something are: well-defined, ill-defined. Very common in legal and academic writing, where something "ill-defined" is often the root of a problem.
ESEN
Suffix · forms adjectives
-defined
Judges how clear the boundaries or meaning of something are: well-defined (clear) versus ill-defined (vague, unclear).
In Spanish: definido / delimitado / con límites clarosIntermediate
Written by Bryan López, English teacher · Updated
How it is formed
Adverb + defined.
- well + definedwell-defined (clear)
- ill + definedill-defined (vague, unclear)
- sharply + definedsharply-defined (crisp, clearly marked)
This is not a productive rule you can apply freely: it is a closed set of fixed expressions. Learn them one by one as set phrases.
How it is pronounced
-defined
Tap the button to hear how the ending sounds. Each word in the table has its own audio.
Examples
Base word
With -defined
In a phrase
- wellwell-definedThe job has well-defined responsibilities, so there's no confusion.
- illill-definedThe rules were so ill-defined that nobody knew what to do.
- sharplysharply-definedThe mountain's sharply-defined edge stood out against the sky.
- looselyloosely-definedHer role at the company is loosely-defined, she does a bit of everything.
- narrowlynarrowly-definedThe contract has a narrowly-defined scope, so extra work isn't included.
Common mistakes
well-defined = simple, straightforward, or uncomplicated
well-defined = precisely specified with clear limits, whatever its complexity
"Well-defined" describes precision of specification, not simplicity of subject. A very complex legal concept can be well-defined — precisely delimited with clear boundaries even if the subject itself is intricate. A simple concept can be ill-defined — imprecisely specified despite its apparent simplicity. The compound judges the quality of the definition, not the complexity of what is defined.
"ill-defined" = vague or unclear (only describes concepts and terms)
"ill-defined" applies to anything that needs precise limits: boundaries, roles, responsibilities, mandates, scope
"Ill-defined" can describe not just concepts and terms but physical boundaries (an ill-defined coastline), roles and responsibilities (ill-defined authority), the scope of a project or inquiry (ill-defined mandate), and any other thing whose precision of specification can be evaluated. The compound is wider than its most common use in conceptual contexts.
A trick to remember it
well-defined literally means "well defined". Not new vocabulary: it is "well" + the verb "define" you already know. Build the compound yourself with ill- when you need it.
Practise what you learned
Exercise 1 · Form the word
Exercise 2 · Pick the right one
"an ill-defined role" is a job...
Frequently asked questions
What does the suffix -defined mean in English?
The suffix -defined judges how clear the boundaries or meaning of something are: well-defined (clear) versus ill-defined (vague, unclear). In Spanish it usually maps to definido / delimitado / con límites claros.
Can you give an example of a word with -defined?
"well" becomes "well-defined". It is a typical example of the -defined suffix.
Other useful suffixes
-founded
Judges how solid the basis of a claim or fear is: well-founded (justified, based on good evidence) versus ill-founded (baseless).
-placed
Judges how well something is positioned: well-placed (in the right spot) versus ill-placed (poorly positioned).
-reasoned
Judges how solid an argument's logic is: well-reasoned (logically sound) versus poorly-reasoned (weak logic).
Learn every English suffix
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