It's easy for one to get fifty in front (6)
I believe the answer is:
facile
'it's easy' is the definition.
(synonyms)
'one to get fifty in front' is the wordplay.
'one' becomes 'i' (Roman numeral).
'to get' means one lot of letters goes inside another.
'fifty' becomes 'l' (Roman numeral).
'in' means one lot of letters goes inside another.
'front' becomes 'face' (face is a kind of front).
'l' placed inside 'face' is 'facle'.
'i' placed into 'facle' is 'FACILE'.
'for' is the link.
(Other definitions for facile that I've seen before include "Easily achieved but of little value" , "Too easily achieved, glib" , "Easy to accomplish" , "Superficial or too easily achieved" , "Smooth" .)