Colonialist discussed aspect of infrastructure (5)
I believe the answer is:
roads
'aspect of infrastructure' is the definition.
'colonialist discussed' is the wordplay.
'colonialist' becomes 'rhodes' (Cecil Rhodes).
'discussed' indicates a 'sounds like' (homophone) clue.
'rhodes' is a homophone of 'ROADS'.
(Other definitions for roads that I've seen before include "Highways" , "Thoroughfares" , "an answer to all clues, initially" , "Surfaced ways" , "Tracks" .)