We don't have synonyms for nucleocide yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are nucleotide, nucleoside and nucleoid.
(n) :
Misspelling of nucleoside. [(biochemistry) an organic molecule in which a nitrogenous heterocyclic base (or nucleobase), which can be either a double-ringed purine or a single-ringed pyrimidine, is covalently attached to a five-carbon pentose sugar (deoxyribose in DNA or ribose in RNA). When the phosphate group is covalently attached to the pentose sugar, it forms a nucleotide.]
(n) :
Misspelling of nucleoside. [(biochemistry) an organic molecule in which a nitrogenous heterocyclic base (or nucleobase), which can be either a double-ringed purine or a single-ringed pyrimidine, is covalently attached to a five-carbon pentose sugar (deoxyribose in DNA or ribose in RNA). When the phosphate group is covalently attached to the pentose sugar, it forms a nucleotide.]