Meaning & use
compos mentis
Last updated
Meanings
adjectiveafter a verbformal
Fully in control of your mind and able to think clearly.
Grammar: Comes after a verb such as be or seem: she was compos mentis; the opposite is non compos mentis.
Patterns
- be compos mentis
- seem compos mentis
Even at ninety, my grandfather is perfectly compos mentis.
The nurse checked that the patient was compos mentis before the form was signed.
She seemed fully compos mentis when she changed her will.
adjectiveafter a verblegal
In law, mentally able to understand what you are doing when making a decision, such as signing a contract or a will.
Grammar: A legal test: a person must be compos mentis to make a valid will.
Patterns
- compos mentis at the time
The court asked whether the writer was compos mentis at the time.
Witnesses confirmed that the defendant was compos mentis.
A doctor must say the client is compos mentis before the sale.
Common combinations
- fully compos mentis
- The judge found him fully compos mentis.
- remain compos mentis
- She remained compos mentis despite her illness.
- not compos mentis
- He was not compos mentis after the fall.
- declared compos mentis
- The patient was declared compos mentis by two doctors.
Synonyms and how they differ
- sane
- Sane is the everyday word, whereas compos mentis is a Latin legal phrase with a more formal tone.
- lucid
- Lucid describes clear thinking at a particular moment, even in someone who is often confused.
- of sound mind
- Of sound mind is the plain English legal phrase with the same meaning.
- rational
- Rational focuses on reasoning, not on a legal state of mind.
Opposites
Word family
- non compos mentis phrase
- not in control of the mind
- mental adjective
- relating to the mind
- mentality noun
- a way of thinking
- competence noun
- legal or practical ability
Commonly confused: compos mentis or compost mentis?
compos mentis vs compost mentis
This is a humorous misspelling; the Latin phrase has no t after the s.
Practice
The lawyer needed proof that her client was ______ when she signed the will.
Choose one answer.
Compos mentis means of sound mind, the legal requirement for signing a will. Non compos is the opposite, and the other Latin phrases mean absent and free of charge.
Make it your own
Write a sentence using “compos mentis”, then check it and compare it with the examples above.