Left poorly after eating yellow bit of broccoli (6)
I believe the answer is:
floret
'bit of broccoli' is the definition.
(I've seen this in another clue)
'left poorly after eating yellow' is the wordplay.
'poorly' is an anagram indicator (a poor spelling).
'after eating' means one lot of letters goes inside another.
'yellow' becomes 'or' (heraldic term).
'left' with letters rearranged gives 'flet'.
'flet' placed around 'or' is 'FLORET'.
(Other definitions for floret that I've seen before include "Part of cauli head" , "Small flower" , "Piece of broccoli" , "Broccoli stem" , "Part of a cauliflower or broccoli head" .)