Girl with land in South America first off (6)
I believe the answer is:
olivia
'girl' is the definition.
(I know that Olivia is a girl)
'land in south america first off' is the wordplay.
'land in south america' becomes 'Bolivia' (country in South America).
'first off' means to remove the first letter.
'bolivia' with its first letter taken off is 'OLIVIA'.
'with' is the link.
(Other definitions for olivia that I've seen before include "Woman" , "- de Havilland, US film actress" , "-- Newton-John, singer" , "Countess in Twelfth Night" , "Female character in Twelfth Night" .)