WordWeb Online

1. Worthy of reliance or trust
   "a reliable source of information";
   - dependable
    
2. Worthy of being depended on
   "a reliable source of information";
   - dependable, honest, true
    
3. Conforming to fact and therefore worthy of belief
   "reliable information";
   - authentic

See also: certain, straight-up [informal], sure, tested, time-tested, tried, tried and true, trustable, trustworthy, trusty, undeviating

Antonym: undependable

Encyclopedia: Reliable