Definition of "ultra" in English

adjective

1. Extreme; far beyond the norm; fanatical; uncompromising.

   • an ultra reformer; ultra measures

noun

1. An ultraroyalist in France.

2. An extremist, especially an ultranationalist.

3. (soccer) An especially devoted football fan, typically organized and participating in choreographies (including pyrotechnics), often of outwardly intimidating demeanour, but distinguished from a violent hooligan (although overlap between both subcultures is possible)

4. (athletics) An ultramarathon.

5. (climbing) An ultra-prominent peak.

6. (usually capitalized) Code name used by British codebreakers during World War 2 for decrypted information gained from the enemy.