Rewriting Yeats up to the moment (2,3)
I believe the answer is:
as yet
'up to the moment' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'rewriting yeats' is the wordplay.
'rewriting' is an anagram indicator.
'yeats' is an anagram of 'AS YET'.
Can you help me to learn more?
(Other definitions for as yet that I've seen before include "Up till now" , "Up to this point in time" , "Thus far" .)