Launch of TV dinners initially rejected (5)
I believe the answer is:
debut
'launch' is the definition.
(I've seen this before)
'tv dinners initially rejected' is the wordplay.
'tv' becomes 'tube' (I've seen this before).
'initially' says to take the initial letters.
'rejected' says the letters should be written backwards.
The initial letter of 'dinners' is 'd'.
'tube'+'d'='tubed'
'tubed' written backwards gives 'DEBUT'.
'of' is the link.
(Other definitions for debut that I've seen before include "Tubed (anag.)" , "Initial appearance" , "entrance" , "Appear in public for the first time" , "First public appearance of performer" .)