(used of opinions and actions) far beyond the norm; "extremist political views"; "radical opinions on education"; "an ultra conservative" 同义词:extremist, radical
Ultra was the designation adopted by British military intelligence in June 1941 for wartime signals intelligence obtained by breaking high-level encrypted enemy radio and teleprinter communications at the Government Code and Cypher School (GC&CS) at Bletchley Park. Ultra eventually became the standard designation among the western Allies for all such intelligence.