Ignoring cute creature would be highly unusual (4)
I believe the answer is:
rare
'highly unusual' is the definition.
(I've seen this in another clue)
'ignoring cute creature' is the wordplay.
'ignoring' indicates named letters should be taken away.
'creature' with 'cute' taken out is 'RARE'.
'would be' acts as a link.
(Other definitions for rare that I've seen before include "Not often seen - underdone" , "Unusual(ly fine)" , "Exceptional" , "Not found often" , "Infrequent; remarkable" .)