Exhausting process? Finally show a leg (7)
I believe the answer is:
wastage
'exhausting process?' is the definition.
'wastage' can be an answer for 'exhausting' (I've seen this before). I am unsure of the 'process?' bit.
'finally show a leg' is the wordplay.
'finally' indicates one should take the final letters.
'leg' becomes 'stage' ('stage' can be a synonym of 'leg'**).
The final letter of 'show' is 'w'.
'w'+'a'+'stage'='WASTAGE'
Can you help me to learn more?
(Other definitions for wastage that I've seen before include "natural decay" , "Useless spending" , "Unprofitable spending" , "Loss through careless use" , "Loss (if natural, without dismissals)" .)