Existing, real (6)
I believe the answer is:
actual
I believe this clue is a double definition.
'existing' is the first definition.
(similar in meaning)
'real' is the second definition.
(similar in meaning)
(Other definitions for actual that I've seen before include "Real, existing in fact" , "Existing in fact, current" , "Real and concrete, not imaginary" , "Real, existent" , "Real, authentic" .)