ultra

going beyond what is usual or ordinary; excessive; extreme.

an extremist, as in politics, religion, fashion, etc.

Ultra, Military. the British code name for intelligence gathered by decrypting German wireless communications enciphered on the Enigma machine during World War II.

a prefix occurring originally in loanwords from Latin, with the basic meaning “on the far side of, beyond.” In relation to the base to which it is prefixed, ultra- has the senses “located beyond, on the far side of ” ( ultramontane; ultraviolet ), “carrying to the furthest degree possible, on the fringe of ” ( ultraleft; ultramodern ), “extremely” ( ultralight ); nouns to which it is added denote, in general, objects, properties, phenomena, etc., that surpass customary norms, or instruments designed to produce or deal with such things ( ultramicroscope; ultrasound; ultrastructure ).