Not as good (5)
'not as good' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for poorer that I've seen before include "Less well-off" , "More impecunious" , "'Having less money, fewer possessions (6)'" , "Less rich" .)
'not as good' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for worse that I've seen before include "less moral?" , "more unpleasant" , "Of poorer quality" , "More awful or unwell" , "Less favourable" .)