Ok about it being limited (6)
I believe the answer is:
finite
'being limited' is the definition.
('finite' can be similar in meaning to 'limited')
'ok about it' is the wordplay.
'ok' becomes 'fine' (synonyms).
'about' means one lot of letters goes inside another.
'fine' enclosing 'it' is 'FINITE'.
(Other definitions for finite that I've seen before include "Limited in extent" , "Circumscribed" , "Fixed" , "Having limits, not endless" , "Of limited size" .)