Faint praise the old regularly ignored (6)
I believe the answer is:
pastel
'faint' is the definition.
'praise the old regularly ignored' is the wordplay.
'praise' becomes 'paste' (I can't explain this - if you can you should give a lot more credence to this answer).
'regularly ignored' indicates alternate letters.
The alternate letters of 'old' are 'l'.
'paste'+'l'='PASTEL'
(Other definitions for pastel that I've seen before include "Soft shade (of a colour)" , "art work" , "Pale or light colors" , "Artist's crayon" , "A light delicate shade of colour" .)