hazel has 4 distinct synonyms spread across 2 of its 5 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
Australian tree grown especially for ornament and its fine-grained wood and bearing edible nuts
the fine-grained wood of a hazelnut tree (genus Corylus) and the hazel tree (Australian genus Pomaderris)
any of several shrubs or small trees of the genus Corylus bearing edible nuts enclosed in a leafy husk
a shade of brown that is yellowish or reddish; it is a greenish shade of brown when used to describe the color of someone's eyes
1 of the 5 recorded senses carries no synonym, antonym or related term, so it is not shown above. Every sense, with its definition and examples, is on the full entry for hazel.
Synonyms, antonyms and the broader and narrower relations for hazel come from Princeton University’s WordNet. Full sources and licences.