testimony by word or deed to your religious faith | (military) a secret agent hired by a state to obtain information about its enemies or by a business to obtain industrial secrets from competitors |
someone who sees an event and reports what happened | a secret watcher; someone who secretly watches other people |
a close observer; someone who looks at something (such as an exhibition of some kind) | |
(law) a person who attests to the genuineness of a document or signature by adding their own signature | |
(law) a person who testifies under oath in a court of law | |