countable often plurala natural physical or mental ability that most people havefaculty of: the faculty of speech
mental faculties (=the ability to think clearly): He had not lost his mental faculties.
critical faculties (=the ability to make judgments about things): For the moment her critical faculties seemed to have deserted her.
be in full possession of your faculties (=have all the normal mental and physical abilities): Mrs. Findlay was in full possession of all her faculties.