adj. 1) in general, able to act in the circumstances, including the ability to perform a job or occupation, or to reason or make decisions. 2) in wills, trusts and contracts, sufficiently mentally able to understand and execute a document. To be competent to make a will a person must understand what a will is, what he/she owns (although forgetting a few items among many does not show incompetency), and who are relatives who would normally inherit ("the natural objects of his/her bounty") such as children and spouse (although forgetting a child in a will is not automatic proof of lack of competency, since it may be intentional or the child has been long gone). 3) in criminal law, sufficiently mentally able to stand trial, if he/she understands the proceedings and can rationally deal with his/her lawyer. This is often broadly interpreted by psychiatrists whose testimony may persuade a court that a party is too psychotic to be tried. If the court finds incompetency then the defendant may be sent to a state mental facility until such time as he/she regains sanity. At that time a trial may be held, but this is rare. 4) in evidence, "competent" means "relevant" and/or "material." Lawyers often make the objection to evidence: "incompetent, irrelevant and immaterial" to cover all bases.