He will love a greeting (5)
I believe the answer is:
hello
'a greeting' is the definition.
(hello is a kind of greeting)
'he will love' is the wordplay.
'will' becomes 'll'.
'love' becomes 'o' (In tennis, 'love' means 'zero').
'he'+'ll'+'o'='HELLO'
(Other definitions for hello that I've seen before include "A salutation" , "Look at that" , "glossy magazine" , "opener?" , "Welcome" .)