I must leave a hairy creature still (3)
I believe the answer is:
yet
'still' is the definition.
('yet' can be a synonym of 'still')
'i must leave a hairy creature' is the wordplay.
'must leave' is a deletion indicator.
'a hairy creature' becomes 'yeti'.
'yeti' with 'i' removed is 'YET'.
(Other definitions for yet that I've seen before include "Still; however" , "Although" , "Up to the present time" , "To this time, nevertheless" , "Up till now" .)