Ring, getting heartless greeting (4)
I believe the answer is:
halo
'ring' is the definition.
(I've seen this before)
'heartless greeting' is the wordplay.
'heartless' means to remove the middle letters.
'greeting' becomes 'hallo' (I've seen this before).
'hallo' with its middle taken out is 'HALO'.
'getting' acts as a link.
(Other definitions for halo that I've seen before include "that could make one light-headed?" , "Corona" , "Holy ring" , "Luminous ring" , "Imaginary circle over saint's head" .)