Disappoint romantic glossing over first section (5)
I believe the answer is:
intro
'section' is the definition.
(I have seen 'Preliminary section ' mean 'intro' so perhaps 'section' could also mean 'intro')
'disappoint romantic glossing over' is the wordplay.
'over' indicates a hidden word (the clue contains or goes 'over' the answer).
'INTRO' is hidden within 'disappoint romantic glossing'.
'first' is the link.
(Other definitions for intro that I've seen before include "One starts" , "Instrumental part at start of song" , "First bars of a piece of popular music" , "Lead-in" , "Opening bars of a song" .)