be compos mentis

To be sane or mentally competent. "Compos mentis" is Latin for "of sound mind." I doubt that Travis was compos mentis when he committed that crime.
See also: compo, mentis

non compos (mentis)

Not sane or mentally competent. The phrase is Latin for "not of sound mind." Based on the orders he's been giving lately, many believe him to be non compos. The judge ruled that she had been non compos mentis at the time, and thus could not be held legally liable.
See also: compo, non

be ˌcompos ˈmentis

(from Latin, formal or humorous) having full control of your mind: Are you sure she was fully compos mentis when she said that?
See also: compo, mentis
References in classic literature ?
There was first the deed or sentence of divorce from his wife, and the full evidence of her playing the whore; then there were the certificates of the minister and churchwardens of the parish where she lived, proving that she was buried, and intimating the manner of her death; the copy of the coroner's warrant for a jury to sit upon her, and the verdict of the jury, who brought it in Non compos mentis.
The essay's point of departure is O'Callaghan's insistence that verbum mentis is for Aquinas not a philosophical doctrine but "a properly theological topic.
It also identifies her as the main spy because the King was often too drunk to be ``compos mentis.
He has perjured himself by neglecting his promises to marry her legally in Athens, and the poet exploits this "perjurium" in Ariadne's pejorative characterization of Theseus: "postquam cupidae mentis satiata libido est, / Verba nihil metuere, nihil perjuria curant" (After the lust of their greedy mind is satiated, they [the male sex] fear no longer the effect of their words, they care nothing for their false oaths).
Algo tragico hay que vislumbrar en la intimidad de ese oficio donde la verdad ha sido un mentis continuo a los logros pregonados del pais y sus gobiernos, un paisaje de sombra, impunidad, mentira, corrupcion y fracaso.
NAB's chief customer officer for Business and Private Banking, Angela Mentis, said, 'Small business owners are critically time poor and this restricts their ability to expand and create new jobs.
com)-- MENTIS Software, the leading provider of sensitive data security solutions for the enterprise, today announced that Suresh Sundaram has joined its leadership team as Executive Director to oversee strategy, marketing, and corporate development.
I've known people have a single half and feel the effects whereas others could easily drink four or five pints and still be compos mentis.
mendous win for mentis Under-14s to beat Tollesby Athletic This was Eleme almost two years October, 2009.
The elderly and less compos mentis would suffer most and there would be no-one to help.
Esta cantidad de aspirantes que consideraron reunir los requisitos para ocupar tan alta responsabilidad son un mentis para los que dicen que el pueblo de Mexico no tiene su autoestima elevada.
For a start they need a new manager, a compos mentis chairman, a couple of strikers and a midfield who can pass the ball.
Jummana, in the same ownership as Nayyir, looked a bright prospect for next year when carrying the colours of the stable's good miler to an easy four-length win over Compos Mentis.