age has 10 distinct synonyms spread across 5 of its 8 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 rejuvenate.
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.
how long something has existed
“it was replaced because of its age”
an era of history having some distinctive feature
“we live in a litigious age”
a time of life (usually defined in years) at which some particular qualification or power arises
“she was now of school age”
a late time of life
“old age is not for sissies”
begin to seem older; get older
“The death of his wife caused him to age fast”
Synonyms, antonyms and the broader and narrower relations for age come from Princeton University’s WordNet. Full sources and licences.
make older
“The death of his child aged him tremendously”