A drapery that’s hard to break is falling down? (9)
I believe the answer is:
avalanche
'falling down?' is the definition.
The answer and definition can be both to do with motion as well as being verbs in their base form.
Maybe they are linked in a way I don't understand?
'a drapery that's hard to break' is the wordplay.
'drapery' becomes 'valance' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'that's hard' becomes 'h' (abbreviation used in pencil classifications).
'to break' means one lot of letters goes inside another (inserted letters break the word apart).
'valance' enclosing 'h' is 'valanche'.
'a'+'valanche'='AVALANCHE'
'is' acts as a link.
Can you help me to learn more?
(Other definitions for avalanche that I've seen before include "Slide of large amounts of snow or stone" , "big fall" , "Slide of a large amount of snow down a mountain" , "Large fall of snow or rocks" , "Rock-fall" .)