Find descriptive alternatives for top secret. Secret mission synonyms and Secret mission antonyms. Understand secret mission meaning and … secret mission synonyms and antonyms in the English synonyms dictionary, see also 'secret agent',secrete',secretly',secretion', definition. Top synonyms for secret operation (other words for secret operation) are covert operation, undercover operation and sting operation. Synonyms for top secret at Thesaurus.com with free online thesaurus, antonyms, and definitions. Top synonym for secret mission (another word for secret mission) is covert operation. Secret Operation synonyms. Search secret mission and thousands of other words in English definition and synonym dictionary from Reverso.