That man will love welcome (5)
I believe the answer is:
hello
'welcome' is the definition.
(both are greetings)
'that man will love' is the wordplay.
'that man' becomes 'he' (he refers to a man).
'will' becomes ''ll' (contracted form, as in 'he'll' - 'he will').
'love' becomes 'o' (love means zero in tennis).
'he'+'ll'+'o'='HELLO'
(Other definitions for hello that I've seen before include "Conventional word of greeting" , "Surprised cry" , "Expression of greeting" , "Introductory greeting" , "Meeting greeting" .)