Feel the softest of feathers then come back to earth (5,4)
I believe the answer is:
touch down
'feathers then come back to earth' is the definition.
I can't judge whether this definition defines the answer.
'feel the softest' is the wordplay.
'feel' becomes 'touch' (touch is a kind of feel).
'the softest' becomes 'down' (I can't justify this - if you can you should believe this answer much more).
'touch'+'down'='TOUCH-DOWN'
'of' acts as a link.
Can you help me to learn more?
(Other definitions for touch down that I've seen before include "Land" , "Reach end of flight" .)