It's easy once I get 50 in front (6)
I believe the answer is:
facile
'it's easy' is the definition.
(synonyms)
'i get 50 in front' is the wordplay.
'get' means one lot of letters goes inside another.
'50' becomes 'l' (Roman numeral).
'in' indicates putting letters inside.
'front' becomes 'face' (synonyms).
'l' going into 'face' is 'facle'.
'i' placed inside 'facle' is 'FACILE'.
'once' is the link.
(Other definitions for facile that I've seen before include "Smooth" , "Lacking depth, argument say" , "Arrived at without due care or effort" , "Oversimplified" , "Lacking depth, glibly superficial" .)