engineer has 10 distinct synonyms spread across 3 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.
a person who uses scientific knowledge to solve practical problems
the operator of a railway locomotive
design as an engineer
“He engineered the water supply project”
plan and direct (a complex undertaking)
“he masterminded the robbery”
Synonyms, antonyms and the broader and narrower relations for engineer come from Princeton University’s WordNet. Full sources and licences.