It means "beyond" (5)
I believe the answer is:
ultra
'it means beyond' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ultra that I've seen before include "Project started at Bletchley Park in 1939 to break the Enigma code" , "Prefix meaning extreme or excessive" , "Extremely; an extremist" , "Far beyond the norm" , "extraordinary" .)