Lover without love — ever without heart (5)
I believe the answer is:
wooer
'lover' is the definition.
(wooer is a kind of lover)
'without love ever without heart' is the wordplay.
'without' becomes 'wo' (abbreviation of 'without', normally with a slash).
'love' becomes 'o' (love means zero in tennis).
'without heart' says to hollow out the word (remove centre letters).
'ever' with its centre taken out is 'er'.
'wo'+'o'+'er'='WOOER'
(Other definitions for wooer that I've seen before include "Romantic type" , "Suitor" , "One who goes to court" , "One courting" , "person to court" .)