sycamore has 9 distinct synonyms spread across 4 of its 4 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.
any of several trees of the genus Platanus having thin pale bark that scales off in small plates and lobed leaves and ball-shaped heads of fruits
Eurasian maple tree with pale grey bark that peels in flakes like that of a sycamore tree; leaves with five ovate lobes yellow in autumn
thick-branched wide-spreading tree of Africa and adjacent southwestern Asia often buttressed with branches rising from near the ground; produces cluster of edible but inferior figs on short leafless twigs; the biblical sycamore
Synonyms, antonyms and the broader and narrower relations for sycamore come from Princeton University’s WordNet. Full sources and licences.