From Longman Dictionary of Contemporary Englishsagesage1 /seɪdʒ/ noun 1 
[uncountable]DFC a herb with grey-green leaves2 [countable] literaryINTELLIGENT someone, especially an old man, who is very wise
[uncountable]DFC a herb with grey-green leaves2 [countable] literaryINTELLIGENT someone, especially an old man, who is very wiseExamples from the Corpus
sage• You are a teen-aged phenomenon with the body of a full grown man and the mind of a sage.• Every last Eve should have her Adam, according to the tiny, self-appointed sage.• It was quite accidental that we planted Cleveland sage, a shrubby California native, next to where I park the truck.• I will be spared the perils of a close encounter with the current Limnititzker sage.• Having learned from that sage, I planted scented geraniums along the narrow part of the driveway.sagesage2 adjective literary GOOD/EXCELLENTvery wise, especially as a result of a lot of experience sage advice —sagely adverbExamples from the Corpus
sage• Gabriel gets sage advice from Archie, the twin who died when they were little.• The correspondent, however, was sage enough to emphasise that the relationship was far from causal.• They were sage young people and got on with Christopher.Origin sage1 1. (1300-1400) Old French sauge, from Latin salvia, from salvus; → SAFE12. (1300-1400) → SAGE2 sage2 (1300-1400) Old French Vulgar Latin sapius, from Latin sapere; → SAPIENT 