Heartlessly swap present for compass (6)
I believe the answer is:
sphere
'compass' is the definition.
(thesaurus)
'heartlessly swap present' is the wordplay.
'heartlessly' says to hollow out the word (remove centre letters).
'present' becomes 'here' (both can mean in attendance).
'swap' with its centre removed is 'sp'.
'sp'+'here'='SPHERE'
'for' acts as a link.
(Other definitions for sphere that I've seen before include "Shape of the Earth" , "All-rounder" , "Perfect round" , "Field; globe" , "Area of activity" .)