Good, clear network (4)
I believe the answer is:
grid
'network' is the definition.
(grid is a kind of network)
'good clear' is the wordplay.
'good' becomes 'g' (abbreviation).
'clear' becomes 'rid' ('rid' can be a synonym of 'clear').
'g'+'rid'='GRID'
(Other definitions for grid that I've seen before include "Framework of crossing lines" , "Electricity network" , "Network of horizontal and vertical lines" , "Rectangular lattice" , "entries in this" .)