incognito

 
Pronunciation: /ˌɪnkɒgˈniːtəʊ, ɪnˈkɒgnɪtəʊ/

adjective & adverb

  • (of a person) having one’s true identity concealed: [as adjective]: in order to observe you have to be incognito [as adverb]: he is now operating incognito

noun (plural incognitos)

  • an assumed or false identity: she is locked in her incognito

Origin:

mid 17th century: from Italian, literally 'unknown', from Latin incognitus, from in- 'not' + cognitus (past participle of cognoscere 'know')