Ignore foul: undeniable try (4,1,5,3)
I believe the answer is:
turn a blind eye
'ignore' is the definition.
(I've seen this before)
'foul undeniable try' is the wordplay.
'foul' indicates anagramming the letters.
'undeniable'+'try'='undeniabletry'
'undeniabletry' with letters rearranged gives 'TURN A BLIND EYE'.
(Other definitions for turn a blind eye that I've seen before include "Pretend not to notice" , "Ignore -- brush aside" , "Refuse to acknowledge" , "Affect not to notice" , "Deliberately be oblivious" .)