Happy to be back from Italy again (3)
I believe the answer is:
gay
'happy' is the definition.
(similar in meaning)
'back from italy again' is the wordplay.
'back' shows that the letters should be reversed in order.
'from' indicates a hidden word.
'yag' is hidden in the letters of 'italy again'.
'yag' in reverse letter order is 'GAY'.
'to be' is the link.
(Other definitions for gay that I've seen before include "Light-hearted, carefree" , "Brightly coloured" , "Merry" , "John --, author of 'The Beggar's Opera'" , "Homosexual" .)