Politician, one investing in evasive business (7)
I believe the answer is:
company
'business' is the definition.
(company is a kind of business)
'politician one investing in evasive' is the wordplay.
'politician' becomes 'mp'.
'one' becomes 'an' (I've seen this in other clues).
'investing in' indicates putting letters inside.
'evasive' becomes 'coy'.
'mp'+'an'='mpan'
'mpan' going into 'coy' is 'COMPANY'.
(Other definitions for company that I've seen before include "two, apparently?" , "Group of soldiers, business" , "See 10" , "Commercial business" , "Fellowship" .)