increment has 2 distinct synonyms spread across 2 of its 2 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 decrement.
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 process of becoming larger or longer or more numerous or more important
“the increase in unemployment”
the amount by which something increases
“they proposed an increase of 15 percent in the fare”
Synonyms, antonyms and the broader and narrower relations for increment come from Princeton University’s WordNet. Full sources and licences.