Heather loses a man (4)
I believe the answer is:
eric
'man' is the definition.
(I've seen this before)
'heather loses a' is the wordplay.
'heather' becomes 'erica' (I've seen this before).
'loses' suggests deleting specific letters.
'erica' with 'a' removed is 'ERIC'.
(Other definitions for eric that I've seen before include "- Sykes, British comedian" , "..... the Red was Norwegian 10th Century exployer" , "Ernie's comic partner" , "Blair, perhaps" , "- the Red, discoverer of Greenland" .)