Clear, after ascent, exercise unfinished — bit of a climber? (7)
I believe the answer is:
tendril
'bit of a climber?' is the definition.
'tendril' can be an answer for 'climber?' (I've seen this before). I'm not certain of the 'bit of a' bit.
'clear after ascent exercise unfinished' is the wordplay.
'clear after ascent' becomes 'ten' (I can't explain this - if you can you should believe this answer much more).
'exercise' becomes 'drill' (military exercise).
'unfinished' means to remove the last letter.
'drill' with its last letter removed is 'dril'.
'ten'+'dril'='TENDRIL'
Can you help me to learn more?
(Other definitions for tendril that I've seen before include "Climbing plant's attachment" , "shoot to gain support" , "Part of plant that clings for support" , "Climbing plant's grasper" , "Feature of plant" .)