Shirker (6)
'shirker' is the definition.
(I know that shirker can be written as slacker)
This is the entire clue.
(Other definitions for slacker that I've seen before include "One shirking work" , "Person avoiding work" , "One evading responsibility" , "Not as tight" , "less tense" .)
(Other definitions for evader that I've seen before include "One who avoids tax" , "Dodger" , "Person who avoids" , "One avoids or circumvents" , "One escaping by guile" .)