Current agreement, perfect (5)
I believe the answer is:
ideal
'perfect' is the definition.
(similar in meaning)
'current agreement' is the wordplay.
'current' becomes 'I' (physics symbol).
'agreement' becomes 'deal' (deal is a kind of agreement).
'i'+'deal'='IDEAL'
(Other definitions for ideal that I've seen before include "Nonpareil" , "Just right" , "Ailed (anag)" , "Perfect; a standard of perfection" , "Perfect but not likely to become a reality" .)