Standard (legal?) phrase for a clear mind

phrase-requests legalese

Is there a standard (possibly legal) phrase to denote that a person has a clear mind and is capable of doing things well and understanding the consequences of their actions (as opposed to being e.g. drunk, high or sedated)?


There is the phrase "being of sound mind" which is often seen in a legal context.
One lawyer discusses the phrase in this page.

The Oxford Dictionaries has the following definition in its lengthy entry for sound, as the first meaning of the adjective.

sound
ADJECTIVE
1 In good condition; not damaged, injured, or diseased.
he was not of sound mind

Related

What is the district police called?
difference between "hypocritical" and "projection"
Word for one nation taking the culture of another
Word order in sentences starting with "How"
Meaning of "textbook Launch" in given sentence?
The difference between "being with a company" and "being from a company"
Looking for the grammar terms to describe the components of a question
What does "numbers" mean here?
Is there any one word to describe people who don't prefer the product?
Is "but on what grounds did not appear" ungrammatical?
Difference between adverb and adverbial adjunct
Term or Title That Embraces the Juxtaposition of Work and Fun