absorb has 18 distinct synonyms spread across 6 of its 9 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 emit.
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.
become imbued
“The liquids, light, and gases absorb”
cause to become one with
“The sales tax is absorbed into the state income tax”
assimilate or take in
“The immigrants were quickly absorbed into society”
Synonyms, antonyms and the broader and narrower relations for absorb come from Princeton University’s WordNet. Full sources and licences.