response has 4 distinct synonyms spread across 4 of its 7 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 result
“this situation developed in response to events in Africa”
a bodily process occurring due to the effect of some antecedent stimulus or agent
“a bad reaction to the medicine”
Synonyms, antonyms and the broader and narrower relations for response come from Princeton University’s WordNet. Full sources and licences.
a phrase recited or sung by the congregation following a versicle by the priest or minister
the speech act of continuing a conversational exchange
“he growled his reply”
the manner in which an electrical or mechanical device responds to an input signal or a range of input signals