plant has 13 distinct synonyms spread across 6 of its 10 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.
place something or someone in a certain position in order to secretly observe or deceive
“Plant a spy in Moscow”
put firmly in the mind
“Plant a thought in the students' minds”
buildings for carrying on industrial labor
“they built a large plant to manufacture automobiles”
Synonyms, antonyms and the broader and narrower relations for plant come from Princeton University’s WordNet. Full sources and licences.
(botany) a living organism lacking the power of locomotion
an actor situated in the audience whose acting is rehearsed but seems spontaneous to the audience
something planted secretly for discovery by another
“the police used a plant to trick the thieves”