Compete with prospect (4)
I believe the answer is:
view
'prospect' is the definition.
(I know that prospect can be written as view)
'compete with' is the wordplay.
'compete' becomes 'vie' (synonyms).
'with' becomes 'w' (abbreviation).
'vie'+'w'='VIEW'
(Other definitions for view that I've seen before include "Aspect, scene" , "Watch TV, e.g." , "Aspect - prospect" , "benefit of picture window" , "The range of the eye" .)