Relative currency thus invested in outskirts of Gabon (8)
I believe the answer is:
grandson
'relative' is the definition.
(grandson is a type of relative)
'currency thus invested in outskirts of gabon' is the wordplay.
'currency' becomes 'rand' (I've seen this before).
'thus' becomes 'so' (synonyms).
'invested in' means one lot of letters goes inside another.
'outskirts of' says to hollow out the word (remove centre letters) (only letters on the outskirts).
'gabon' with its middle taken out is 'gn'.
'rand'+'so'='randso'
'randso' placed within 'gn' is 'GRANDSON'.
(Other definitions for grandson that I've seen before include "Male offspring, third generation (8)" , "Young male relative" , "Junior relative" , "Male child of one's child" , "Younger male relative" .)