Foreign banker loves keeping Republican in touch regularly (7)
I believe the answer is:
orinoco
'foreign banker' is the definition.
(South American river - something that banks)
'loves keeping republican in touch regularly' is the wordplay.
'loves' becomes 'oo' (two O's - 'love' means zero in tennis).
'keeping' indicates putting letters inside.
'republican' becomes 'r' (abbreviation).
'regularly' indicates alternate letters (regularly take one letter, leave next etc.).
The alternate letters of 'touch' are 'oc'.
'r'+'in'+'oc'='rinoc'
'oo' enclosing 'rinoc' is 'ORINOCO'.
(Other definitions for orinoco that I've seen before include "Great river in the north of S America, flows through Venezuela" , "O, I croon about the river" , "banker" , "South-American river" , "may be seen running through South America" .)