/ ˈtrʌsti; NAmE / adjective , noun
■ adjective
[ only before noun ] ( old use or humorous ) that you have had a long time and have always been able to rely on
SYN reliable :
a trusty friend
She spent years touring Europe with her trusty old camera.
■ noun
( pl. -ies ) ( informal ) a prisoner who is given special advantages because of good behaviour