We don't have synonyms for preverb yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are proverb, reverb and prevert.
(n) :
(grammar) A separable verb prefix or a particle that precedes a verb.
(n) :
(grammar) Any of a class of words in the Chinese language whose function is analogous to the cases, prepositions, and postpositions of other languages.
(n) :
(grammar) A verbal prefix in the Algonquin languages whose function is analogous to the adjective of other languages.
(n) :
(grammar) A separable verb prefix or a particle that precedes a verb.
(n) :
(grammar) Any of a class of words in the Chinese language whose function is analogous to the cases, prepositions, and postpositions of other languages.
(n) :
(grammar) A verbal prefix in the Algonquin languages whose function is analogous to the adjective of other languages.