Swedes maybe in Costa Rica wearing shirt under jumper (4,4)
I believe the answer is:
root crop
'swedes maybe' is the definition.
(Swedes are a root vegetable)
'costa rica wearing shirt under jumper' is the wordplay.
'costa rica' becomes 'cr'.
'wearing' means one lot of letters goes inside another.
'shirt' becomes 'top' (I've seen this in another clue).
'under' says to put letters next to each other (below, in a down clue).
'jumper' becomes 'roo' (short for kangaroo).
'cr' placed inside 'top' is 'tcrop'.
'tcrop' after 'roo' is 'ROOT-CROP'.
'in' acts as a link.
(Other definitions for root crop that I've seen before include "Tuber, beet, etc" , "Eg, potatoes" , "Vegetable" , "Potatoes or carrots" , "Maybe Murphy" .)