implant has 4 distinct synonyms spread across 2 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.
become attached to and embedded in the uterus
“The egg fertilized in vitro implanted in the uterus of the birth mother with no further complications”
put firmly in the mind
“Plant a thought in the students' minds”
a prosthesis placed permanently in tissue
Synonyms, antonyms and the broader and narrower relations for implant come from Princeton University’s WordNet. Full sources and licences.