Trust  —n. 1 firm belief in the reliability, truth, or strength etc. Of a person or thing. 2 confident expectation. 3 responsibility (position of great trust). 4 commercial credit (obtained goods on trust). 5 law a arrangement whereby a person or group manages property on another's behalf. B property so held. C body of trustees. 6 association of companies for reducing competition etc. —v. 1 place trust in; believe in; rely on the character or behaviour of.