Allowed to ignore starter? That's terrible! (5)
I believe the answer is:
awful
'terrible' is the definition.
(I know that terrible can be written as awful)
'allowed to ignore starter?' is the wordplay.
'allowed' becomes 'lawful' (I've seen this in another clue).
'to ignore starter?' means to remove the first letter (I've seen 'ignoring starter' mean this).
'lawful' with its initial letter taken off is 'AWFUL'.
'that's' acts as a link.
(Other definitions for awful that I've seen before include "The pits" , "Dreadful and dire" , "shocking" , "gruesome!" , "Appalling, terrible" .)