WordNet records no synonym and no antonym for subscription. It is the only member of each of its synsets, which is common for technical, taxonomic and single-sense vocabulary — there is no other English word that means the same thing. The broader and narrower terms below are the useful relations in that case.
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 payment for consecutive issues of a newspaper or magazine for a given period of time
agreement expressed by (or as if expressed by) signing your name
a pledged contribution
Synonyms, antonyms and the broader and narrower relations for subscription come from Princeton University’s WordNet. Full sources and licences.
the act of signing your name; writing your signature (as on a document)
“the deed was attested by the subscription of his signature”