Has yeti barely been seen up to now? (2,3)
I believe the answer is:
as yet
'up to now?' is the definition.
(I've seen this before)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for as yet that I've seen before include "Up till now" , "Thus far" , "Up to this point in time" .)