delay has 10 distinct synonyms spread across 5 of its 6 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. Its one recorded opposite is rush.
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.
act later than planned, scheduled, or required
“Don't delay your application to graduate school or else it won't be considered”
time during which some action is awaited
“instant replay caused too long a delay”
the act of delaying; inactivity resulting in something being put off until a later time
Synonyms, antonyms and the broader and narrower relations for delay come from Princeton University’s WordNet. Full sources and licences.