Notice fewer without blemish (8)
I believe the answer is:
spotless
'without blemish' is the definition.
(I've seen this before)
'notice fewer' is the wordplay.
'notice' becomes 'spot' (I've seen this before**).
'fewer' becomes 'less' ('less' is associated in meaning with 'fewer').
'spot'+'less'='SPOTLESS'
(Other definitions for spotless that I've seen before include "free from sin" , "Without blemish" , "Above reproach - perfectly clean" , "Perfect" , "Extremely clean" .)