instrumentation has 2 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.
an artifact (or system of artifacts) that is instrumental in accomplishing some end
the act of providing or using the instruments needed for some implementation
the instruments called for in a musical score or arrangement for a band or orchestra
the act of arranging a piece of music for an orchestra and assigning parts to the different musical instruments
Synonyms, antonyms and the broader and narrower relations for instrumentation come from Princeton University’s WordNet. Full sources and licences.