WordNet records no synonym and no antonym for topicalization. It is the only member of its synset, 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.
(linguistics) emphasis placed on the topic or focus of a sentence by preposing it to the beginning of the sentence; placing the topic at the beginning of the sentence is typical for English
“`Those girls, they giggle when they see me' and `Cigarettes, you couldn't pay me to smoke them' are examples of topicalization”
Synonyms, antonyms and the broader and narrower relations for topicalization come from Princeton University’s WordNet. Full sources and licences.