Relating to rural life (6)
'relating to rural life' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for bucolic that I've seen before include "Agrarian" , "Relating to rural life" , "Characteristic of country life" , "Rustic - pastoral" , "Of rural or pastoral life" .)
(Other definitions for rustic that I've seen before include "unrefined" , "Rural - simple" , "Citrus (anag)" , "Rural, countrified" , "Simple and unsophisticated as of the countryside" .)