Might notice her become disheartened around cliff edge, maybe (5)
I believe the answer is:
sheer
'might notice her become disheartened' is the definition.
I can't judge whether this defines the answer.
'around cliff edge maybe' is the wordplay.
'around' is an insertion indicator.
'cliff' becomes 'sher' (I can't justify this - if you can you should believe this answer much more).
'edge' says to take the final letters (I've seen 'edge of' mean this (one of the letters on the edge of the word)).
The final letter of 'maybe' is 'e'.
'sher' placed around 'e' is 'SHEER'.
Can you help me to learn more?
(Other definitions for sheer that I've seen before include "Absolute - precipitous" , "needing to change a course" , "Very fine or vertical" , "Very fine like silk stockings" , "Very steep or diaphanous" .)