"Easy!" (2,4)
'easy' is the definition.
(synonyms)
This is all the clue.
(Other definitions for facile that I've seen before include "Glib or fluent (6)" , "Easy to accomplish" , "Superficial or too easily achieved" , "Easy, simple" , "Over-simple, superficial" .)
'easy' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for simple that I've seen before include "Mean" , "Effortless" , "The sort of interest" , "Penniless pie seeker" , "A piece of cake" .)
'easy' is the definition.
(similar in meaning)
This is all the clue.
(Other definitions for effortless that I've seen before include "a breeze?" , "Requiring no physical or mental exertion" , "Not showing any strain" , "easy" .)
'easy' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for nothing to it that I've seen before include "piece of cake" , "It's not difficult" , "Add this to multiply a number by ten" , "dead easy!" .)
'easy' is the definition.
(I know that easy can be written as light)
This is all the clue.
(Other definitions for light that I've seen before include "free gift from The Sun" , "dawn" , "Not dark; not heavy" , "See 19" , "Easy to digest; flame" .)
(Other definitions for go slow that I've seen before include "A deliberately retarded pace as in industrial action" , "Work-to-rule" , "Non-energetic sort of workers' protest?" , "Lazy sort of industrial action?" , "Delaying form of industrial action" .)
(Other definitions for too that I've seen before include "As well; in addition" , "Likewise" , "As well, also" , "What a pity!" , "To a greater than desirable extent" .)