(of witnesses) The legal capacity of a person to be a witness. Every person of sound mind and sufficient understanding is generally competent as a witness. A child is competent to give evidence unless it appears to the court that the child is incapable of giving intelligible testimony. However, a child below the age of 14 years may only give unsworn evidence. The spouse or civil partner of an accused is generally competent and compellable as a witness for the defence, and is also competent (but not normally a compellable witness) as a witness for the prosecution.